I’ve seen U2, Jethro Tull, Aerosmith, Yes, etc. dozens of times. As professionals, when the clock strikes 9PM the show starts without fail.
She is just showing her contempt for the audience.
The Jethro Tull frontman, Ian Anderson, has done some interesting jazz and classical stuff in the past couple of decades. Mo betta than his top 40 rock stuff, IMO.