It's true that the world doesn't end if Dr. Jones isn't allowed to go the movies, or if Mr. and Mrs. Smith get to watch the end credits before finding out that their baby's in an ambulance. But the world also doesn't end if you have to suffer through a rude teenager on the phone for a minute and a half. You talk like your leisure experience is an absolute moral imperative, but everyone else's is just frivolous goofing off and easily sacrificed. Why is that?
The goal of a movie theatre is leisure experience. If you know a movie is 90+ minutes, and there's a significant likelihood of you or your devices causing a disruption to the other 100 people in the audience in 90+ minutes...
On a different note, me and my friend and his wife went to see Roger Waters perform The Wall a couple years back. The tickets said "No photography", but the band was very careful to say "When you take photos, please make sure the flash on your cameras is off. There are effects during our production that camera flashes will disrupt." I'm paraphrasing, but they were projecting video on the bricks that were assembled onstage as part of the performance. Sure enough, not minutes into the first set, flash flash flash flash flash.
My friends were taking photos. I made sure not to look over at them.
I've been to the cinema several hundred times over the last decade. There was a period we used to go 1-2 every week. In that time, I've never once been distracted by anyones phone going off. Maybe half a dozen times I've been momentarily annoyed by someone checking their phone with an overly bright screen. That's it.
It would seem letting people have a signal doesn't have to be a problem.
> The goal of a movie theatre is leisure experience. If you know a movie is 90+ minutes, and there's a significant likelihood of you or your devices causing a disruption to the other 100 people in the audience in 90+ minutes...
I think your definition of "disruption" may not be entirely reasonable. It's one thing if someone is sitting there having a chat during the movie, but if a person quietly getting up and excusing themselves (in response to an unheard vibration in their pocket) is unacceptable, then we're going have to ban anyone who sits down to a three-and-a-half-hour film with a Jumbo Big Gulp from the concession counter.
If that was the reaction to an incoming cellphone call, every time by every person, I don't think anybody would have a problem with cellphones in public spaces.