No major disasters, but I don't do this a whole lot. However, we (a bunch of friends and myself) were invited to play for a Christmas program at a local park/historical site. We've been playing together for 12 years and have been playing at this particular venue twice a year for their pioneer reenactments for about as long. We started out as representatives of a local music club but since we were the only ones who ever came--the park is a bit too far north of the city for most people--and we were having some other issues with said club, we decided to break off and form our own group. We have always played the reenactments as volunteers, but some of the other entertainers are paid. Anyway, our "band leader" asked the park if, just this once for the Christmas party, we could be paid SOMETHING. The park representative agreed to $100 apiece for about four of us to play in the afternoon and then for a dance in the evening (this meant playing much longer, incidentally, than any other performers, paid or not).
However, they told our leader on the night of the dance that they didn't have our checks and would send them later. It took them TWO MONTHS to finally hand over the money and we found out later that they hadn't actually budgeted to pay us and that the person who agreed to do so had not had the authority to approve it. We felt a bit bad for taking money from a park because we all know they never have enough funding, but we also felt like we should always be expected to put on a good show for free. Ironically, the Christmas dance was a special event for volunteers so we were, in a sense, working our own awards dinner.
We still volunteer for pioneer days but if they ever ask us to play for Christmas again, we're getting it in writing.