Befuddled

I work for a non-profit organization - meaning, as we all know, the organization doesn't rake in the mula. Yes, we have enough money to pay the bills & keep the organization going should the economy fail to recover & the members drop off.

We have an annual conference every year for the membership & to make this conference run the way it should, we require volunteers from the membership - people to head up meetings, people to serve as moderators of sessions, people to do multiple tasks throughout the 4 days we are there.

In order to coordinate all of these details, we request the volunteers to give their availability and interest. We also clearly state they may be called upon to serve more than one time, in different sessions, on different days, etc.

So... why do I get emails about people who are 'surprised' when they are assigned 2 sessions???

Or emails from people who have volunteered, been assigned their tasks & then tell me they aren't going to be at the conference AT ALL?

Or emails from people who don't like the task they have been assigned? Can i change it for them?

Sometimes I think it would be easier to have PAID people doing these jobs! As long as that paid person isn't me =)