Folk music is supposed to be "the people's music" (which may be an arguable point), but the idea has always more or less been that it was "homegrown" entertainment, and an alternative to "commericial" entertainment--and a lot of people feel like it, and everything connected with it, should always be as close to free as practically possible. Given the nature of our world, this can be very amusing at times.

People periodically invited our band to play for events with the idea that we would do it without charge, because it was "folk music"--and occasionally someone would become irate when we quoted our fee.

In this same vein, I knew a performer who was booked regularly by a certain individual for a particular organization's special events--one day, she got a call from another person from the organization who booked another of the events. When she finished, and requested her pay, she was told that the booker had always assumed there was no fee because it was folk music.