If you can't live 2 hours without worrying about your children, maybe your children would be better off with parents less paranoiac than you.
Sorry, but that's nonsense.
The only chance my wife & I have these days to go to the cinema is when our son is in daycare. If anything was happen to him while there, they need to call us. If we're not reachable, they could call social services, and how would that look? So we need to be contactable while our son's there.
Having said that, my phone's always on silent when in the cinema, and I would leave the auditorium to take the call should I happen to receive one. That's just common courtesy - something most cinema-goers, parents or not, don't seem to have these days.