No phones on stage. Period. Shut it off. My God ... we've taken a turn for the worst when we act like the teens that have it permanently attached to their body. I've been a leader on a few nice dates and the band members attempted to have their phones on ... "attempted" (key word here). I told them - "no phones on stage" - no phone - or no job.
It's really a question of work ethics - none of us needs to be accountable 100% of the time.