The only time I want lip-synching and air guitar is when the sods are totally drunk/drugged like the Ozzie concert I saw at the Nassau Coliseum. Ozzie truly sucked that night. Thankfully, Queensryche made up the difference as the opening act.
I've walked out on a few headliners for just that reason. Steven Stills in the late 70's comes to mind. If I had wanted to see a coked out guy play bad notes on guitar all night, I could have stayed in the dorm.
I saw Elton John in concert just a couple of months ago. There were a LOT of l-o-n-g intros and piano interludes to try to hide the fact that he just doesn't have the endurance he had as a younger man. I'd prefer it that way to a tape.