There are far better ways to address people holding up their phones to record than to outright ban them from everyone. There are strong reasons (Bataclan) to need and have those there.
What's with the sympathy for the performer? It's hard for them to even see the audience. Most of the light is focused on them and the audience is in the dark.
What's the better way? I'm not saying phones need to be physically removed from people, just kept in pockets/bags/whatever.
As for my comment about the performer, I'm just picturing it from their perspective and to me it would feel odd to go from looking at people to looking at phones. I'm sure there are lots of people who film with their phone lights on, so that's got to be noticeable through the stage lights.
What's with the sympathy for the performer? It's hard for them to even see the audience. Most of the light is focused on them and the audience is in the dark.