A friend of mine just posted that a club he went to had these (in NYC). He loved it, thought the club was far more "human".
As to time: theaters would have to hire more ushers, methinks, to make it work.
My bigger concern would be that the people that hide their phones, would be the people most likely to be rude with it anyway!
If we're not having fun, then why are we doing it?
These are DISCUSSION boards, not mutual admiration boards. Discussion only occurs when we are willing to hear what others are thinking, regardless of whether it is alignment to our own thoughts.