Been there myself.. Several years back the blues band I played in got this type of crap all the time. The money was decent, and I was able to use it as my only income.. (Sure miss those days...) We played numerous gigs where we were told a specific number of people, and then later to find out it was twice what we were told. After a while we just said the hell with it and started lugging ALL of our equipment around in the van for cases like that. It is funny how people seem to think keyboardist know EVERY song out there and get pissed off if you don't know the request. I've also played several solo gigs where I was duped quite a bit.. I think my best solo gig I did was a small wedding anniversary where I only had to provide a total of a 1/2 hour of music. Got a free meal, and $200.00 cash from it.. The only gear I had was a keyboard, stand and speakers....

Squeak