I have been to preview screenings were phones were bagged and kept outside to be picked up later. If the cinemas could do it without infuriating patrons further, I'm sure those up the chain would be keen to encourage it.
I think that would be frowned upon for the same reasons cell/gps jammers are. Creates a potential for lack of prompt emergency response during unexpected situations that often occur when people gather.
I recall the patent[1] by Apple that was aimed at turning off recording functionality at events, with a concert being used as an example. Cell service left intact while your device's sensors refuse to cooperate with recording a video.
Of course that creates a whole other set of potential problems now doesn't it? :)
