Thanks for all the replies; I'm still bothered a bit by this though. For me, part of the entertainment at a ceilidh is the interaction with the band, and the sheer enjoyment of listening to live music produced by musicians I can see. I suppose what I'm really worried about is what has happened elsewhere in music; it's much harder for four or five piece bands to get gigs when your local pub venue can book a DJ or a karaoke for much less. The expectation of what is a reasonable fee for a night of music is driven down, and making any kind of living from music gets harder. I'm also reminded of what a friend said about this; he compared going to a DJ session with a visit to the cinema 'Do you want to go to the pictures tonight?' 'Dunno; who's the projectionist?'.
Tim