We have had the interesting experience with a couple of rock rands from the 60’s and 70’s who still think it is “cool” to make the audience wait in anticipation for their grand entrance on stage.
At a recent corporate event, the stage manager for a “rock band” listened to the rehearsed band introduction by a corporate sponsor and then told the band to “go on in 5 minutes”.
When we work with rock bands at corporate shows we always have five minutes of music and simple lighting effects planned to fill the five minutes the band waits to go on stage. We call it "the five minute drill." Hopefully you will never have to use it, but the "five minute drill" is a good thing for a production team to have in their back pocket.