My company requires us to use a "burner" phone and laptop when we travel internationally. I can helpfully print out the policy from the employee handbook and show it to the border guard. I'm not sure that's considered as suspicious as you think absent any other suspicious behaviors.

I think saying something like "I bought a cheap phone for the trip because I don't want to lose my good one." should be good enough?

Simpler is better for these types of situations, so I agree!

>Just make sure you use it for a few days before hand so it doesn't appear to be a burner phone

Wouldn't they notice all your mail, call list, and other such accounts are from a few days?

> use it for a few days before hand so it doesn't appear to be a burner phone

No need to bother.

Most companies of any size, and us civil servants, have policies to travel with burner phones/laptops when crossing (even some benign) international boarders and/or entering certain countries.

Frankly, it is so commonplace, it is not remotely suspicious to travel with a burner.