Cell Phone Jammers

I thought the article in the New York Times on devices used to block cell phone signals was helpful, seeing as I had no idea such a thing existed. I look at those devices as an immature and dangerous tool. They may seem like a good idea, if in a sitiuation such as the example in the article about a man who didn't want to listen to the girl's conversation, sitting next to him. In other cases blocking calls can be dangerous if there's an emergency, and one person is trying to call another, but cant.