I was in an NFL stadium yesterday for a High School championship game. The stadium furnished the professional headsets (even though we'd brought our own). This apparently also happens for the real deal, thus decreasing the likelihood of any interception (because it's not their equipment, dammit)
Besides, in the locker rooms they have huge warnings about artificially influencing the outcome of a game like that. It's not worth your career.
Also, in other NFL procedures news, all the uniform rules for the players are posted in two formats - one big poster full of text and one easy-to-use graphical poster. Low IQ, anybody? I wish I'd taken a picture, I had the camera and everything, but I saved all the tape for the game footage.