I just completed an interview wit the great Hilary Hahn, who will perform with the Utah Symphony in mid-November.
Here is one of the questions, and interesting answer she gave:
Q: You have been quoted as saying, "Great music can be quite comfortable and relaxing, and you can sleep—as long as you don't snore." If you ever caught someone sleeping during a performance of yours, wouldn't you be offended?
A: No, I wouldn’t be offended at all! The important thing is that the person has a positive experience. Being hypnotized by music to the point that you drift off to another place isn’t as bad as it seems. And anyway, you shouldn’t sit there focusing on staying awake. You’ll miss all the best parts! Follow the music and the things that interest you, instead.