I think I'm just part of the present crowd - depends....<snip> do it, but minimize the appearance or blend it into the stage somehow.
I do this - iPad down low used as a teleprompter for lyrics. Kinda like what Petty is doing, but on a budget! Saw Ozzy do this a long time ago as well on his Live at Budokan DVD.
I do lead vox in one band but have horrible memory for song names and some lyrics. I might refer to the lyrics five or six times during the night where we'd play 45 songs. Usually, if I'm having trouble, I'll only need the first two or three words of a phrase to carry me through - it's a safety net to ensure a quality show, not a distraction. I call it "production". ;-)
I control the screen with a bluetooth foot pedal and usually advance to the next song during the ending of the last song, so it's even less obtrusive.
