In case of an emergency people should follow staff's directions; preferably without being glued to their phones and without disrupting any ongoing rescue attemp

In case of an emergency people should follow staff's directions; preferably without being glued to their phones and without disrupting any ongoing rescue attempts by trying to take a good video... The only relevant exception are professionals on call (i.e. doctors, police etc) - and they'll make the conscious decision to not attend such a concert unless explicitly exempted from the phone ban. Everybody else may vote with their wallet. Personally, I'd pay a premium for concerts that enforce a no-phone policy.