If it were real, it would be the greatest thing ive ever seen, but i have to doubt it because:

* im pretty sure someone would have to sign a waiver to allow you to do something like that to them

* his behavior was unpredictable. what if instead of firing the gun, he walked up and bashed the actor in the face with the butt of it until he dropped? or what if he freaked out and turned the gun to his head and nailed a paintball point blank to his temple. There'd be a lawsuit somehow.