It sounds like enough to win a lawsuit. The burden of proof is more likely than not. If they have software that tells them the names of the songs that were playing, then that is pretty damning evidence.

Sure, you could have renamed your songs, but who is going to believe that?

I've thought about using last.fm but didn't for this very reason. Wasn't it obvious to everyone that at some point CBS would avail themselves to the information that their subsidiary was collecting?