Ban the Phone!
I'm with the majority of *sensible* people here, if I've paid my money for a (expensive) ticket to watch a film I really, really, really don't want to listen to some teenager with verbal diarrhoea talk crap on their phone. BTW., it is usually teenagers, but I've noticed a growing number of adults as well.
I've always said to friends and family: if it's an emergency (fire/medical/crime) dial 999, anything else it *can* wait!! My phone its firmly switched off when inside and turned on once film is finished, for the social idiots it's called being considerate! And no, I wouldn't hand over my phone to a total stranger!!
Better, they should implement some sort of electronic blanking system which would switch of in the event of an emergency. That way the social retards would realise that they're there to watch the film!
Sadly, can't see it happening any time soon!