cell phone jammers

It is annoying hearing somebody else talk on a cell phone in public. I don't want to hear half of their conversation. I don't mind short conversations, long and loud ones bother me. I don't think people should use jammers though. If there is some kind of emergency within the area that is being blocked a person couldn't call for help. People should relize when and where to use a cell phone. They are aware of their surroundings and not were it would bother people. Leaving a room to talk on the phone affects one person but using a cell phone jammer affects everybody in that area.