1. Password protect your smartphone, and if you are compelled to surrender it to a crooked cop, do your best to turn it off or lock it before you let it go. 2. You are under no obligation to review your photos or videos with anyone, and you cannot be legally compelled to do so by any cop or security person. 3. Once you have taken a picture or video in the U.S.A, there is NOBODY who has the legal authority to demand or force you to delete that picture without an order duly signed by a judge.