I appreciate the argument but the artists are getting paid for this so I'm somewhat less concerned for them. On the other hand, I'm paying for a ticket and those fuckers are a 'real real problem' for me!
I applaud Ms Bush's request and the polite wording of it. I would be even more impressed if she added that it ruins the experience for all the other people, who might just want to watch the show rather than someone's phone.
Waving around those fucking glowing rectangles is the the very definition of selfish - those doing it are inconveniencing and annoying everyone else and detracting from the experience for the sake of their own, individual, wants.