I'm not a fan of blocking cell coverage in theaters. I would prefer that the theaters be a lot more strict about it. If your phone rings, you're texting, or actually talking on the phone, you should be kicked out. If your phone vibrates and you leave the theater to accept the call and then come back in, that should be fine (once or twice).
Imagine how pissed you would be if you're at a 3 hour movie and a loved has a horrible accident and people try calling you 10 minutes into the movie. 3 hours later you get the message and by the time you get to the hospital, they're dead. Or, you're out to the movies and the babysitter calls 'cause your kid ate some peanuts and the babysitter doesn't know where you keep the epi-pen so the kid has to take a trip to the hospital so his throat doesn't close up and now you've got a huge bill to pay 'cause the insurance has a huge deductible on ambulance rides.
People need to be responsible with their technology, we shouldn't have to block it. Remember those stupid digital watches that beeped every hour or had some alarm that would go off? We didn't need to ban or block those, people eventually learned how to use them properly.