At Tapestry Folkdance Center in Minneapolis, we actually came to the conclusion some years back that we were OVERcompensating our volunteers. We were handing out free passes right and left, sometimes for pretty minimal effort, and one of our board members did an analysis that persuaded all of us that it was affecting income. We especially noted that large numbers of free passes were used when high-profile performers appeared, which cut into their income (because they got a straight percentage of the door). 

We put a reform into place when I was on the board. We stopped giving members a bunch of free passes with membership. For contra, if the volunteer effort allows one to dance (i.e. end-of-the-night cleanup), you get into the dance for free but don't get anything on top of that. If the volunteer effort significantly prevents you from dancing a large chunk of the dance (admissions, sound), you get a free pass for another time. Committee work doesn't get you any passes. Callers and musicians are considered paid performers and not volunteers, and get no passes.

Our other programs also shifted along similar lines, but were modified to fit their circumstances. Our family dance, for example, has always operated on a shoestring budget and does not compensate volunteers at all -- and we initially paid performers so little it was basically volunteering. But by last year, we had developed a solid enough following that we were able to increase performer rates. Yay!

David