Why cant people spend two solid hours and not look at their cell phone?

The other night I went to see the new movie To Rome With Love. I will review that movie this week. But for now, it is safe to say it didn't hold my attention and I was looking elsewhere other than in the direction of the screen. That got me thinking of a topic I have been meaning to blog about for ages now. So, I will today.
When I was growing up, my idea of Movie Phone was the old skit on Seinfeld.

These days however, movie phone means the endless amount of iphones and blackberries that are glowing in the movie theater like a bunch of candles at a night concert in the park.
Sure, they now give you the obligatory message before the movie to turn the cellphone off before the movie begins
because it is disturbing and inconsiderate to your fellow moviegoer. That used to work when they were just phones and the only thing you had to consider was that they would ring. However, it seems to me that the patrons have taken this to mean that they must turn the ringer off, but not the actual phone. Why is this?
Simply, an iphone or blackberry is not a phone anymore and hasn't been for a very long time. The fact of the matter is that they are now multimedia centers for playing music, games, checking social media and email and just about anything you can think of. A lot of people now use them as a GPS mechanism as well as assorted other things. Is it any wonder that those who bring it to the theater (which is about 99% of the patrons) think they cannot go two hours without looking at it and simply just watch the movie and enjoy the company of the person or persons they came with.
So, my solution is this: Jam the signal so it doesn't work within the inside of the theater. If you came to watch the movie, watch the movie. If you cannot do that, then don't come. 
Of course, that wont happen. Many patrons would simply complain and if they didn't get their way, they wouldn't come to the theater. So, it wont happen. Just another reason why eventually I wont see movies in the theater anymore.