[Organizers] ASCAP and BMI

I just got a letter from ASCAP asking payment of license fees for use of recorded and copyright materials at our dances. If my organization ran just our contra dances, I'd tell them to take a hike - or not respond at all - with the argument that our contras use only traditional public domain music, and not recorded music nor copyright arrangements. However, my organization also has waltz, swing, DJ, and Cajun/zydeco series, where I don't think I can make the same assertion. The net is I'll probably go ahead and pay. My question: What encounters (and resolutions) have other groups had with ASCAP (and BMI too, for that matter). Thanks, RL -- Rob Lindauer