I recently attended a Joey Alexander concert at SFJazz. Aside from a clear "no photograph" policy, there are also attendants watching people and reminding them

I recently attended a Joey Alexander concert at SFJazz. Aside from a clear "no photograph" policy, there are also attendants watching people and reminding them if they took their phones out. It's working but definitely didn't cover all high-profile concerts like the ones featuring Jack White.