Just from watching him. He saw me taking pictures of him once...in Philly during SYW...and was actually trying to help me out a bit by stopping his movement for a second and I would snap one second too late. He did this a couple of times and then laughed at me because my reflexes were kind of crappy.
Nice to know I amuse people sometimes
To be on the safe side, take a disposable. If they confiscate it, you haven't lost a "real" camera.