I once bought a router to use for my internet when I moved into my new house just to find out that it "wasn't compatible" with Verizon's service. I still have it (because I'm terrible about returning things). Is there any point in keeping it? Is there anything fun or interesting that I could do with it?
Potentially you could serve them a captive portal. I thought about this a while back, basically to create a sneakernet WiFi network where people could connect directly to a landing page that had my music for download, for example.
That would be a great thing to setup at an airport (somewhere people sit around for hours, bored). So long as it's done to advertise your music and not to be malicious. I'm assuming your music isn't "Nails on a chalkboard" or "A baby crying", that could both be music and malicious.