So the system requires each subsection of a shelf to have a working weight sensor? Is that really do-able in a shop where the general public will be repeatedly knocking, bashing and generally ill-treating it? Most regular stores that I've been in will have plenty of wonky looking shelves, broken shelf tickets and so on...
If a sensor fails, presumably Amazon is going to lose track of, or at least, lose accuracy in tracking of, some product. The cameras aren't a foolproof backup for this (since, if they were, why bother with the complexity and expense of weight sensors at all?) To me it suggests that these stores are going to need a hell of a lot of maintenance.
I'd agree, but we already have the imperfect ones you get from self-service checkouts, and they work a decent enough amount of the time they might suffice?
It's the more human element that'll be interesting to me - you see people pick something up and put it back in the wrong place all of the time. Just think about the poor staffer who'll get the "item in the wrong place" ping through their headset every 30 seconds. Am assuming Amazon will use skeleton crews to run these, so they'll be rushed just picking up the pieces (quite literally).
The self-service checkouts is a good point - but in my experience at least 10% of those are regularly out of service, and they are large systems that are meant to be robust. I can't see how that will scale up to thousands of product lines. As you say though, the staff will probably be far more busy replacing items...
> It’s a bit overkill, I think, to replace a checker or self-checkout stand with a hundred cameras that unblinkingly record every tiny movement. What’s to gain? 20 or 30 seconds of your time back?
My thoughts exactly. What's the point of all this? What is the problem that they're trying to solve?
Also, the monitoring done in that kind of store is very different from security monitoring systems we have today, because it knows who it's watching. The fact that it doesn't use facial recognition is pointless since it has your identity and account # the minute you enter the store.
It can study you: not just what you buy, but how you think.
I'm also curious if it would work with how I shop. Usually in small supermarkets I put my bag or trolley in one corner of the shop and bring products back to it. It's maybe a little inefficient but it lets me walk unencumbered. Would it know my bag is mine?
I don't understand this "20 or 30 seconds" comment, it takes more like 20 minutes to wait in line and scan all items, then pay. I use Uber mainly because I can walk out the cab without paying, and that's a real twenty seconds.
In France we have these manual scanners that you can carry around the supermarket and scan items as you put them in your bag. Then when you exit the store, semi-randomly an employee will rescan part of your items, or all of them (it happens more often if you often forget to scan things - which can happen, but it can also be wilful shoplifting of course). Then you pay and the gate opens.
Most of the time it does take about 30 seconds, also you don't have to get your stuff out of your bag and you know all along how much you're going to pay.
I think I haven't used the regular lines for years.
>Most of the time it does take about 30 seconds, also you don't have to get your stuff out of your bag and you know all along how much you're going to pay.
And this latter has an interesting side effect.
At the time these readers were introduced the "message" to the public was "your convenience, faster checkout" (while actually the reason was "let us reduce the number of cashiers").
What was soon found out was that the "poor man's average shopping" was raised by some 10-15%.
Imagine you go to the supermarket and you only have in your pocket a single 50 Euro (or 50 dollars) note.
You put things in your basket making a mental calculation of the total amount in order to avoid, when you checkout, if the total is more than 50, to have to leave some item (and also to avoid the "social shame").
With the new method, where you can see your progressive total, that kind of shopping has raised from 42-45 to 48-50, i.e. people use "all they have" without risking to "look bad".
When I'm using the app-based version of this kind of system, I find myself much more likely to put an item back on the shelf when I see the price come up in the app (or when I notice how high my total bill is getting).
Being surprised at the total spend after visiting a supermarket used to be quite common for me, and I'm sure I'm not alone in that experience!
Of course Amazon are well aware of this psychology and only send you the bill after you leave the store...
>who is this hypothetical poor man who's so bad at managing money that an exact total of the amount he's spending will cause him to overspend ?
It is not hypothetical, it is a peculiar - but not so uncommon - man/woman with a limited amount of money in his/her hands (and of course no credit card or similar), the single 50 in the example (but it could be 20 or 100) banknote.
He/she is willing to spend the whole amount of money, but before didn't because he/she was afraid to be seen as having only that given limited amount of money and by making approximate mental calculation tended to undereestimate (or if you prefer preferred to be on the safe side).
With the barcode reader he/she can spend the whole amount of money he/she has available with no risk of appearing (to the cashier, to the people in queue) as "poor".
The poiont is not that with the new system this kind of "poor" people overspend, rather it is that before it underspent.
As long as there's nobody in the queue, and the "scannette" (yes, that's how they're called) still has enough battery, and you haven't tried to buy razor-blades which require a manual action from an attendant to remove the theft-protection device, and the granny in front of you isn't trying to pay with coins.
Never had a problem with battery or a queue that lasted more than a minute or so (either at Carrefour or Auchan, some of the largest ones in Lille).
The manual action doesn't take long because the attendant has little to do, and I don't use the lane where you can pay with cash, but the many others that only take a credit card.
20-30s is just flat-out unheard of where I live (east coast). It doesn’t happen - not in Costco, not in Stop&shop, and certainly not at TJs.
Removing check-out times from my Saturday morning shopping routine - which, as it includes hitting three stores for the various best deals and exclusive products my household prefers, guarantees a wait of 20+ mins in at least one of the shops - would probably give me back 40-60 minutes in total.
Supermarket checkouts in France are woefully slow and ineffecient. I've lived here for 10 years, and it drives me crazy.
- Cashiers do not pack for you. (Most other countries, they will bag as they go. Groceries are plonked on the other side.
- ..which means that the cashier cannot / will not progress with another client until the previous person has packed their stuff. This can take.. a .. long .. time.
- You can still pay via cheque in a supermarket. This requires cutting the cheque, manually sighting two pieces of ID, scanning the cheque, processing the payment. The little scanner devices take.. 30 seconds to do a scan.
- Stores are horribly understaffed. They constantly have 20% less people that they should.
So you move to the self-checkout machines, that constantly error if you place an item too quickly / slowly / on top of another item.
There are definitely pain-points to solve in this area.
We have to pack ourselves in the UK too, but it doesn't take long you just put things in bags as they're scanning the next one. Or in Aldi where they fire things through like a machine gun, put it in your basket / trolley and go and pack it elsewhere.
it depends where you live. in NYC I have waited in line for on the order of 10 minutes before. in podunk I have never waited (supermarket wait is actually one of the only things I complained about after moving to NYC)
I would love this! I usually go shopping with a backpack, and in a store like this I could put stuff into my backpack directly from the shelf, rather than trying to put all my items into my bag as quickly as possible at the checkout counter with half a dozen impatient people behind me.
Also, shoplifting. 1.7% of gross sales, which given 2% profit margins, you can see how profit can almost double with this. It's a 32B dollar opportunity.
Economy of scale will also help reduce worker costs.
What’s to gain? 20 or 30 seconds of your time back?
Lines at my local Safeway are always really long. Yesterday I went in for a single item and there was no express checkout lane open. It took seconds to find the item, but 15 minutes to check out.
That's because they don't want to hire more staff. The kind of store that would invest in hundreds of cameras (plus other sensors) would already have enough checkouts to avoid queues.
Can you write a blog post about that, it seems very strange and unique. Isn't being a cashier a terribly tedious, mindless and repetitive job extremely ill-suited for a human?
We must be very careful in deciding what others find fulfilling. We are not all cut out for the same levels of social interaction and we don't all have the same aspirations. I have met many a cashier/grocery/retail worker who were very happy people and I have met some who weren't. it all comes down to filling your financial needs as well as your personal needs and more power to those who can
Anecdotal bit:
Years ago I did programming/etc for a rent-a-cop agency. We had thousands of uniformed security people working across the country both armed and unarmed. Since I had responsibility for ensuring payroll runs were completed to include termination pay; some states required 48hr pay; I was initially appalled at the hourly rates some had.
Well after talking with more than a few; our local office was in the same building and we had one guard on hand for escorting women to and from the parking deck; I came to find out more than a few enjoyed the work. One even commented "I get to sit behind a desk all day and get paid" and students who did work got to study.
I think the Author of the article misses the point. It's slightly more useful for consumers, but once this becomes commoditized and scaled out there will be massive cost savings compared to hiring a handful of checkout staff, and this system could run 24 hours without having to close down the store.
They don't solve any problems, they are trying to record your offline life so that they have the full picture of your existence and manipulate it in order to maximise the profit of shareholders.
Existing stores could catch up a lot by improving the self checkout experience. Perhaps add a super-express method for single items with e-receipt only.
It's strange that news organizations take such a cynical tone with new technology. Really? "Surveillance-powered convenience store"? Are we suppose to call TechCrunch a "surveillance-powered ad powerhouse"? Or Tesla "surveillance-powered vehicles"?
All stores are already equipped with security cameras to prevent theft. When you're in someone's shop, you don't have an expectation of privacy. Amazon merely took it one more step and made it easier for you to checkout.
An entire generation has now grown up with the idea that this level of surveillance is not only ok, it's actually odd to think differently. What's worse is the level of govt surveillance, after all i can just, not go to the creepy Amazon store..
In just a few short years, people who have never known life without the patriot act or the fear and anxiety of walking into an airport unmolested will be voting.
I agree with you in principal. But I'm far less hopeful that meaningful solutions will come. After all, it's not been them that has enacted these secret courts, fisa, patriot act, ndaa, weaponizing govt ( irs, fbi, dhs, ...), that's been their role models, us. All in the name of safety.
Part of the OP's point is that there currently are cameras in almost every store, and then you provide your identity by credit card at the end. It's not that much creepier than now.
This is an interesting position to me. To paraphrase Lawrence Friedman, privacy is, pretty clearly, a recent invention. If anything, we're the first generations growing up with a concept of what privacy really means.
I am personally a huge fan of privacy as a right. But, like free speech, it's not necessarily practical or desirable for it to be an absolute right. There's a line to be drawn in the sand, and it's purely subjective.
The bottom line is, with the current way we draw the lines, there's practically no expectation of privacy in a store. You could be filmed. End of story. You can also be filmed at work, which I feel is a lot less comfortable, but still understandable.
I think a lot of the problem is coming down to people's fear of what this could be used for, but we can't just stop making new things because the systems will be abused and subverted by bad actors. We need regulations that adapt faster to these problems. Regulations are already lagging hard on internet privacy, AI, etc. and it will continue to be far behind if something isn't done.
There's no doubt that technology can be bad. Frankly, I don't think web browsers should execute arbitrary code for every page you visit. But for every new technology, there's usually just as many ways it could be used for evil as it is for good. Your privacy in the modern age could be dramatically improved if there was no such thing as a digital camera, but that doesn't mean a world without it would be better. Cameras were not required to have horrible corruption, bad actors, or evil corporations; all of those existed long before. Technology, on the other hand, illuminated these issues to the everyday person.
If there's anything I want society to be addressing, it's how we're letting companies collect untold amounts of private information, sell it, use it in algorithms to try to manipulate society, and very often, accidentally allowing their entire databases to leak. All in the name of targeted advertising? The free lunch of unfettered, irresponsible data collection needs to end. Strictly regulating how devices can transmit and collect data could help a lot with almost every case that was mentioned, including Amazon's new stores, self-driving cars, and targeted ads.
> If anything, we're the first generations growing up with a concept of what privacy really means.
This is a kind of historical revisionism that I don't like that inflates the self-importance of the now merely because we don't know how things will turn out in the future.
During the founding of the United States, privacy was very much a central issue. In fact, the Third (third!) Amendment to the Constitution was to prevent the invasion of privacy by an armed soldier of the government literally being imposed on a family's residence, and Fourth Amendment protected a person's privacy against unreasonable search and seizure.
Yes computers are a novel twist, but to suppose no one back then "really understood what privacy means" I find to be a form of ignorance bordering on historical condescension.
I would argue that rights against unreasonable search and seizure isn't the same thing as privacy. That being said, rights against unreasonable search and seizure is also a recent invention in the grand scheme of human history.
It’s inflammatory, but imho a valid concern — Amazon is probably going to link all your purchases there with your profile on Amazon, so it’s quite a leap in how much it enhances their ability to surveil you — while tempting you with the discounts that such detail enables.
Almost every large Retail store has a lot of Stuff going on with Video Analytics (eg: Store Front). With this one, Amazon has just upgraded the retail benchmark and ported their digital KPIs to Retail store. I think this is no way worse/stronger than Amazon.com tracking (except your faces show up).
Well... I think you're right that the headline is pretty biased. I also think that it's kind of reasonable to be a bit stressed out that the entry level for the labor market is about to get a whole lot higher as robots become more affordable and sophisticated. I know I'm changing the subject a bit but I think that it is reasonable to bring this up because I think that in a lot of cases, people are willing to accept pretty much any demonization of things that scare them, which I think the news media is aware of.
I don't know what else you'd want to call it. It does use surveillance technology and does invade privacy a lot more than normal convenience stores. Not using the word "surveillance" here would in my opinion be more biased than using it. The store just is what it is, whether you want to be excited about this new technology or not.
Yeah, at least Amazon took the seemingly obvious step of painting all objects in the ceiling black as to at least attempt to mask their surveillance. I sort of hate looking towards the ceiling at stores like Target which have those black domes which contrast so hard against their white ceilings dispersed every 5 ft. It being so noticeable makes it feel all the creepier.
This comment is something an apologist of surveillance would write.
Yes, it is a surveillance powered store. That’s what it literally is. Just like Alexa and Google Home are literal always-on listening devices in your home.
Edit: A bit more context in case someone misunderstands. New technology can improve one’s life exponentially. But it is simulataneously capable of exacting great harm.
But Alexa and Google Home aren't always on listening devices in your home -- at least not any sense that matters. They are always-on, and they do have microphones, but they are not recording every conversation and sending it to the mothership. You need to affirmatively request them to listen (via OK Google/Alexa/whatever hotword) before they are listening in a sense anyone should be concerned about.
Everything in modern society is "surveillanced". The highways you drive on (highway cameras), the news sites you read (ad tracking), the dollars you make (IRS). Someone somewhere knows these things. Specifically pointing out something is "surveillance-powered" without context is agenda-driven.
I agree, but we have to be careful not to give a pass to our industry to do whatever they want.
And it isn’t necessarily agenda-driven by TechCrunch. As you said, they are ads/analytics based. So it follows that they will produce content that gets maximum eyeballs.
I'm not really sure what other avenues one can go down that isn't powered by surveillance that takes the "ease" factor to the next level. Literally without humans there you have computers and the computers have to know who you are. What other possible outcomes are there?
Monero is one new technology that is increasing privacy significantly in an important way. I can't think of many others since they all have large downsides in delivering a better service. Brave for advertising perhaps. I can't think of anything else.
One thing I didn't seem to find any mention of in the article is what happens if you take an item off the shelf to inspect it and then put it back --- or misplace it somewhere else, as often happens with other stores? Hopefully the system can determine that you've left product behind, since otherwise it would negate one of the huge advantages of having a physical store: you can inspect and select before buying.
They cover this a bit in the NYT article. The system knows if you put something back—or rather it seems that it makes sure it always knows what’s in your possession. I don’t think it’s necessarily looking at the shelves as much as it’s constanly trying to determine what objects are associated with each person.
I go to a 7 11 down the street. There is a guy in there that works the checkout. He always greets everyone with the biggest smile youve ever seen and I find myself feeling a little better as I leave.
When I get outside I think to myself, this guy probably does that to every single customer for at least 8 hrs a day. For how much reward? Then I think a little about automation, eat my donut, and head to work.
At my usual supermarket, there's a checkout operator who is so awkward people actively avoid him and prefer queues over his emptier lane.
With a largely automated shop, we lose out on human contact, but then the same applies with online shopping too. On the other hand, I think we'll eventually recall those crazy days where there were checkout operators tallying products. Already when I visit the States, I find it bizarre when there is second person bagging products! The first time I went to China (1991), the department store checkout operators used an abacus to sum sales. Even when they had a cash register, they used it purely for the cash drawer and still favoured the abacus!
Eventually, I think the majority of people will actually not actively make purchasing decisions in entire categories. Choosing and shopping yourself will be a premium thing. In the future, I can see a large swathe of people taking cheaper subscriptions whereby they are delivered products decided by algorithm.
I don't see what is so cynical about 'surveillance-powered convenience store's. Having surveillance in a store doesn't have any negative connotation for me, and 'surveillance-powered' is a good way to describe what makes this store unique
The system knows the weight of the grain container before the customer takes any grain.
It also knows the weight of the container after the customer takes some, so it's not too hard to figure out how much was taken.
There will be exceptions where this is not the case (e.g. grain accidentally spills), but it will work 99.9% of the time, and then as the article mentions, for the other times there will be an attendant to sort out any issues.
If the future of grocery shopping is between grocery delivery that you order over the Internet (linked to your account and browsing habits) or using such a surveillance store, the privacy implications are probably not that different either way. Privacy is already in a bad enough state that stores like that probably don't make a big difference anymore either. They are just more creepy because commerce exclusive to the 'real world' seemed like the last safe haven for privacy (provided you were able to pay in cash and didn't use loyalty cards or other offline cookies).
I also can't help but think that they just put those employees there for PR reasons. No matter how Amazon tries to spin it, a majority of jobs will be lost. Maybe that's inevitable, but then we should face it instead of pretending you can just put them somewhere else in your automated store.
The article says that there won't be shopping baskets or trolleys. You'll carry out what you want in your own bags.
I live in South Australia and since plastic bags were banned from being provided free in stores, the vast majority of people BYO reusable shopping bags. A slim minority buy store-branded plastic bags (15c each), usually when they've forgotten to BYO. It very quickly becomes the default and any complaints dry up.
Do you think they would have opened it if they didn't have a pretty high degree of confidence that it was working? It's been in beta for quite some time.
There are better places to steal from than those with massive numbers of cameras pointed at you from all directions.
> Do you think they would have opened it if they didn't have a pretty high degree of confidence that it was working? It's been in beta for quite some time.
I'm sure they've tested extensively but how are they getting around the issues I mentioned? It feels that even for a human with slow motion cameras it would be hard to 100% track what they're claiming. For example, picture a customer very close to the shelves taking two sandwich items with one hand and dropping them into a bag where the items are getting occluded by each other and the customer's body.
I'm not referring to facial recognition. I'm saying if you shoplift, they are going to be able to provide the cops with video evidence, and they will know who you are.
The bigger problem is if they overcharge too many customers. Having to complain afterwards because it lists items you didn't buy eliminates the advantages of faster checkouts.
That's very true. And if they are not confident about their predictions then it might be difficult to push back when people fraudulently claim to not have purchased something.
Cameras seem like such a crude expensive approach to doing this. And there has to be exploitable holes.
Recently was watching a Western movie where a person goes into a shop. The goods are all behind the counter. The person points out what they want, the clerk retrieves it.
Big vending machines with phone interface possibly. Maybe a full shelf as shown in photo behind wire or glass and a robotic arm like the ones seen in Amazon warehouses. That way people can kick the screen and curse when the robotic arm fails to deliver the correct good and no clerks are harmed in the process.
In what part of the world is 1400sqft considered tiny? That is 130m^2, which would be considered a pretty decent size appartement here in Austria. You don‘t find many appartments as big as that in a city here. (We‘re a family of 4, and we live in a 80m^2 appartement)
I'm in Bangalore and live with my wife. Compared to what our parents, we always complain about how small our living space is. They have lived their lives in small towns/villages in houses with nice large rooms and huge backyards, all of which is only a pipe dream for us now in our 21st storey pigeon-hole.
I always assumed European countries with their lower population densities would be inclined towards larger living spaces than us. Seems like that may not be generally true.
I had to go look up average apartment size in Bangalore to make sure you had the correct number. 130m² is a pretty large apartment size in Europe.
We live in 70m² and find it decently sized. And I work remotely so I'm in it all day long. We pay 800€/month, it would be much higher if we were closer to a city center.
We have a bedroom and a study, even two small bathrooms. It does have a backyard that is not counted I in the size. Most people I know live in similarly sized apartments.
My entire detached house in Redmond, WA is 1200 sq. ft. Though small for the U. S., I don’t know that I’d label it “tiny”, nor do I think your average 7-11 convenience store to be larger than that.
Imagine the exploits! A crowd of high school kids, milling in a tight group, grabbing bottles of wine and putting back bottles of water from under their coats, trading items around, taking cheap cans from one rack and swapping them in for expensive caviar etc on another rack.
Alcohol requires an attendee to check ID before being taken from the shelf. There are other employees on site to monitor, answer questions and restock.
You seem to have the impression that no checkout == no employees. This is not the case.
But if employees still check for accuracy, is the system really faster than a normal supermarket? Can imagine it being only slightly faster for a much higher price. Might work in the beginning when everyone wants to try it but I doubt it can appeal to a wider range of people.
I'm pretty sure this kind of use of surveillance cameras/data wouldn't be legal in the EU, so that's why you might see lots of people who are more enraged by this than they supposedly should be...
You're allowed to put up surveillance cameras and record things, but if you actually want to check the recordings, then there's requirements. The exact requirements probably differ between countries, but I imagine you need at least a well-founded belief that you've been robbed in all of them.
And even just for that use-case, you need to put up signs that make it evident that customers are being surveilled.
For something like this Amazon Go store, you'd probably need people to sign a disclaimer to ensure that they've understood what they're getting themselves into. And you might have to allow an opt-out clause, so that people can choose to not be surveilled and then check out normally.
That last part isn't yet in EU law, I don't think, but with the upcoming General Data Protection Regulation (25th May) it is, or at least it's going to be hard to argue that you don't have to allow opt-out.
But all stores don't have the data-storing and machine-learning capabilities of Amazon. Very possibly, a customer in an Amazon Go store will have images and distinct features of their physical likeness stored by Amazon and linked to their Amazon account. This is much different in spirit than Costco's security cameras, for example.
Not just cameras. They have agents on the ground spying on you too!
Or... they have a security team who monitors cameras and have loss prevention specialists roaming the store. Depends on how you want to spin the wording.
In the wild this tech will get ripped to shreds. The exploits will be endless. And the interesting question is: is it really shoplifting if their system fails to register the sale? Not really, so it is open season.
I think there are ways Amazon could approach this.
1) They can have people review recordings for items that the system is less than sure of and charge the customer accordingly.
2) They could ban customers from the store if they determine that the customer seems to be attempting to subvert the system.
Customers already steal things from stores. In this case, the fact that you have to tap-in makes it a lot less of an anonymous shopping experience which would likely deter people from trying to cheat the system. If people are trying to cheat the system, it seems relatively easy to ban them (compared to a conventional store).
Amazon doesn't need to solve everything. Today, if you claim that you didn't receive a delivered package, what does Amazon do? I'm guessing that they just send another. However, I'd also guess that there's some trigger noting, "this person seems to have way more packages stolen than we'd expect". At that point, you can take action like requiring signatures or shipping to an Amazon locker.
Similarly, Amazon will accept a certain amount of loss combined with the ability to note over time what is going on. The automated system may not be perfect, but presumably humans can review recordings.
Ultimately, the only difference between current retail and this is the assumed intent. If someone walks out of a normal store without checking out an item, it's assumed that they intended to steal it. If someone walks out of an Amazon Go without paying, you assume they intended to pay and the system failed. However, if someone is putting their back to goods and picking them up from behind, that's pretty suspicious looking.
It seems like Amazon's surveillance is meant to capture way more than typical retail and that should allow them to find bad actors easier, even if it requires a little human review.
Seems the scale of the store, the controlled supply of product, and the quality of tracking can essentially undermine most exploit vectors. Perhaps in a larger store, or perhaps with more crowds or variance in product... but as it stands, the Amazon Go store is about 1000 sq ft currently and it has been operating internally, daily, for over a year seeing hundreds of shoppers per day. I assume that if there was any issues they wouldn't be launching this publicly. I'm sure Amazon invites you to come and try to break the system, if you want.
Edit: Other commenters state the sq ft of the store is closer to 1800, still very controllable.
>is it really shoplifting if their system fails to register the sale?
Why wouldn't it be shoplifting here if it is at any other store? If the cashiers and loss prevention officers don't notice you walking out with merchandise in your pocket, is it somehow worse because their eyes and brains are made of flesh instead of plastic and metal?
True. That sounds like a fine excuse for the accidental cases. When you are deliberately making an attempt to deceive the system, that is where it crosses the line.
If you are presenting your items to the system normally and they fail to register it, yes. If you are hiding the item in your jacket or cart to deliberately avoid the cashier's attention, that is shoplifting.
BingoBox has had automated convenience stores in China for months now.[1][2] They're about the size of a shipping container. Amazon is coming from behind here.
Very different tech stack and UX in these products. BingoBox still requires users to scan their own groceries. It's basically the self-checkout line in Safeway.
Something I've not seen an answer to in any article about this concept: I'm slightly above average height, so occasionally people somewhat below average height ask me to reach things down from high shelves in supermarkets.
More questions somewhat in this same vein:
Can you take your family with you? What happens, if your 5-year-old grabs his favorite sweet and brings it up to you to ask you whether he can have it? Can you put things back into the shelves?
If a sensor fails, presumably Amazon is going to lose track of, or at least, lose accuracy in tracking of, some product. The cameras aren't a foolproof backup for this (since, if they were, why bother with the complexity and expense of weight sensors at all?) To me it suggests that these stores are going to need a hell of a lot of maintenance.