A guy I knew in high school rented out a ballroom at a large downtown hotel and paid a relatively well-known (in Canada at least) alternative band $20,000 to play his 17th birthday. He got his parents to front the cash, invited the whole school and charged everybody $40 to get in (snacks/cake/pop included) and easily made a profit, and became the coolest kid in school since he had Sloan actually playing a full concert set at his birthday. It required nothing more than calling up the bands management and telling them he wanted them to play on a certain night and asking how much the fee was. They didn't care what the hell it was for as long as they got paid, within reason of course (I'm sure they wouldn't have played the NAMBLA annual general meeting, for example). It's not uncommon and I don't begrudge any band, KISS included, for doing it, people gotta make a living. There are plenty of other more legitimate reasons to hate on KISS.