Ozzy looks at them a lot for the newer songs, at least from what I noticed. It never bothered me that much. Scott usually doesn't stare at them for entire songs like Ozzy, he mostly looks at them so he knows where he is in a song (so it seems).
I've been watching recent clips of AC/DC playing live, and I noticed Brian Johnson looking at teleprompters too which was kind of a surprise. I'd rather have someone read the words than run over to one side of the stage and make unintelligible noises, lol.