If you're doing business with a religious son-of-a-bitch, get it in writing. His word isn't worth shit. Not with the good lord telling him how to fuck you on the deal.

-- William S Burroughs, Words of Advice for Young People

I have a brother-in-law who used to manage a Christian rock band. He told me that Christian organizations were the worst about paying for performances, because they assumed that the musicians were in it for service to God, not for the money.

But it could also be that the Christian organizations just had less money.