Why should Person A be able to see the photos they are tagged in if the photos have never been shared? If I have lots of albums on Picasa and I never share any of them but I tag everyone in them, that's pretty clearly for my benefit and not the benefit of the individuals in the photos. There's no harm to Person A by being tagged in my private album, nor is there really any benefit to Person A by having the photo automatically shared.
I think it's reasonable to share a photo where Person A is tagged only if the photo has been shared. Tagging and sharing are separate actions as far as most people are concerned so there's not a good reason I can see for the UI performing both actions on a tag event.
Because its me. If you have a picture of me and want to link it to my profile information then I think it would be reasonable for me to know you have that picture. There is obvious benefit for me to have that picture shared with me and aware that it exists instead of it being hidden away in your private collection.
Tagging is sharing. I see tagging as creating a link between the photo and my google+ profile. Maybe there should be a second option of labeling my name but not linking to my profile and thus keeping the label private, which is odd but seems more like what you want.
Do you also think it would be reasonable if Google copied me on your Gmail conversations everytime you mentioned my first name or anything I've created? I don't see how they owe you anything for privately linking to your profile.
It's completely and utterly irrelevant that it's you. I took the picture, it's MY picture. I have thousands of physical pictures captured on 35mm film. I have names and dates written on them, should I have to give a copy of all of those pictures to the people that are in them simply because I put their name on the back? Should I have to give them a copy because I wrote their URL on the back? The additional meta data of the link to your profile is not ANY greater than a simple label so long as that picture is private.
But it isn't irrelevant, I have a vested interest in the picture from the fact that I'm in the picture. Photos of me are extremely valuable to me and I would think most people have that opinion but maybe I'm wrong. This 'force sharing' leads to a Pareto improvement in both the google+ network and society. I honestly do not understand the situation where sharing a picture of me with me makes it less valuable for you.
In the case of physical photos, no I dont think you need to give everyone a copy because that would take effort on your part. Sharing on google+ is costless.
I think it's reasonable to share a photo where Person A is tagged only if the photo has been shared. Tagging and sharing are separate actions as far as most people are concerned so there's not a good reason I can see for the UI performing both actions on a tag event.