TickTockMan
"Repent, Harlequin!"
Not so much with a string quartet, but certainly with a rock band and most extremely certainly with one of the world's biggest rock bands.
But from what I can see on the youtube clips, which is, admittedly hardly a substitute for being there, most of the audience are more interested in taking pictures with their phones and passively consuming what they presented with than getting into a living, breathing rock'n'roll show.
To be fair that was the first show there. A lot of press, bloggers, YouTubers, etc were there just to get pictures and video. The Vegas people I follow didn't care much about U2, they cared about the content they could get out of it.

