*smile* Stewart.. a lady who 'sometimes' comes to our sings is totally blind also. She knows a whole bunch of songs, but sometimes needs help, just like the guy Don F. mentioned.
   She carries a big cloth bag...and in it is her cheat-sheet...in Braille! The funny part is that she hates to be 'seen' using it, so she sits, the bag in her lap, with her hand inside the bag, 'reading' along. She does remarkably well, too..(I can close my eyes and 'usually' not tell)... No one ever mentions that it looks stranger to see that hand rustling in her bag than if she just took the Braille sheets out.
    The whole point is, that she DOES know the songs, and just needs some reminders.

   There is really no clear & obvious 'line' that can be drawn where fun & discomfort diverge , as this is different for everyone, and if I can close my eyes and not tell, then fine....but when someone cannot follow a song, even with a book, they are past the line for me. If they can follow the tune and sing the words without stopping and reading ahead, they are right on the line: even if it is stilted and dull, I will shrug and wait.
    All I usually do anyway is try to set a good example and drop hints...but there IS a small movement growing to make some sort of announcement...maybe printed in the newsletter...suggesting gently that our 'tradition' is to avoid books...and especially THE book...most of the time.

   We shall, as they say, see.