Folk clubs will only suvive if income balances outgoings.
If a club loses money over you then you owe that club because without them there will be less opportunity to promote the music less opportunity to play less chance of getting remuneration.
This is a folk club perspective.The same applies to a bar landlord, so try a be realistic and help perpetuate live music.
Dont ask me for my opinions on people who earn a living at music.