Jamming devices are illegal, no matter what they tell you.
You are making a choice you don\'t have a right to make, because you are affecting people around you to a large degree, and not accepting any concequences yourself. You don\'t know that that guy in the movie theatre isn\'t a heart surgeon who misses his on-call emergency page (which is why most theatres have re-transmitters that make your cell read \'emergencies only\'). You don\'t know that you aren\'t cutting off a call for someone who is talking to someone very important or about something very important or time critical.