Earlier quoted context omitted.
I think the viscerality of this response is fascinating. Putting your phone in a case is a "prison", and you must check it every time you go to the toilet, and you're concerned about a terrorist attack -- enough to want your phone, but not enough to stay home, as if your apps could somehow save you. > Treat people like adults. If they break the rules, ask them to leave. Isn't that what we've been trying for the past…
Taking your phone out at a concern is not misbehaving. It's fine and accepted. What OP is proposing is to make phones prohibited at a concert. Then it will be misbehaving, and you can eject people who are breaking the rule. I think this would be a fine idea.
No. No it isn't. It's selfish and shows an egregious lack of courtesy to other attendees/the performer. The fact that most people do it just reveals most people are arseholes, not that it's 'fine and accepted'.