I play in a band that has to deal with this problem, in that we play a lot of tunes, which is probably what we're most known for, but we do do songs as well, and our lead fiddler Kate Barfield is also a well-respected singer.Basically, we do the obvious thing, we play more tunes if we're playing for dancing, but include more songs if there are a lot of listeners in the audience. I love fiddle tunes, and each one has a different character and charm for me. But I have to face the fact that to 90% of audiences, a fiddle tune is a fiddle tune. All the tunes occupy the same pigeon hole in the mind, labelled "fiddle tune". That's the way it is, and performers need to adjust to the facts of life. If you're going to leave out songs, you must have some very compellingly interesting arrangements for your instrumentals!