There is a special remote control that will turn off nearly any TV. If you have one in your pocket, no one can see it.
He had a wrist watch, by Casio IIRC, that could control tvs and vcrs or dvd players.
When the teacher would put a video in for the kids to watch, he'd turn the machine off when the teacher walked away. The teacher would start the video again and when she'd walk away, the same thing. Then when she went back to start it, the video would start playing again.
Oh to be able to do something like that at an airport. But there are probably some laws in place making it a federal offense to change a tv station from the party designate. There is probably some type of Homeland Security law about using a non authorized remote control device in an airport.