Along the lines of staying sober, I would add that having someone smoking a cigarette right by me when I am there to sing will make me leave out of self-preservation. Some singers are smokers, but for those of us who are not, it helps to have the smoking on the other side of the room or circle if it is in the room at all. In our session, the musicians are non-smokers, or at least they refrain during the session. The smokers that show up to listen seem to be mostly college kids, around 20 years old, and mostly girls.