'The Fiddler would play his best fit, and the "xyz director" would say, "got any more?"'

I didn't think of this, but, based on my very limited experience in show-biz outside playing in pubs, it sounds likely. So a fiddler actually might have put in considerable time preparing 'authentic' material, and then end up having to play something that is more appealing to the director. So I hereby withdraw my snooty insinuations about the fiddlers themselves.