Really? wow.
How common is that in the business?
Not very. But Ozzy has always had a hard time remembering lyrics, there’s live stuff from Sabbath in the 70s which is terrible because he just gets lost and start vamping crap. He went to prompters in the 80s and never looked back. There’s a few guys that cheat once in a while, Mike Ness of Social Distortion has guys come out with lyrics sheets for a handful of songs that just don’t seem to want to stick in his head. I say if you need the tools use the tools.