"And if I were a promoter I wouldn't dream of not paying my DJ's"
Agreed, Why wouldn't DJs be paid, they spend hundreds and sometimes thousands on their collections, and they are booked to play the records they have bought. It's like asking a joiner to build you a kitchen and not paying them cos they can do it or they enjoy doing it. Many DJs, myself included do it as a profession, a job and a means of earning money to live. It's OK doing it for free if that's what you want, or to get your name of flyers etc. for your CV fair dinkum.