I'm not saying people
should take one of these hacked phones to a movie, but I could see where some people might appreciate it.
By making simple modifications to common Motorola phones, researchers in Berlin have shown they can block calls and text messages intended for nearby people connected to the same cellular network. The method works on the second-generation (2G) GSM networks that are the most common type of cell network worldwide. In the U.S., both AT&T and T-Mobile carry calls and text messages using GSM networks.