I’m not sure what point you are trying to argue. The article at the top of this thread says the venue paid a public performance licensing fee for the song. To use it in the future, the campaign would have to pay that fee, as well, and unless Heart withdraws from the umbrella agreement under which the song’s royalties are paid, McCain would be doing nothing wrong. That’s exactly what Rush does. As far as specific details of the agreements and royalties - I have no idea, and unless you are an attorney specializing in this field, I doubt you do either.
I think you agree with me that it would be dumb for the campaign to pick a fight over this. In addition, I think it is dumb for Heart to make a stink just because somebody liked their song enough to play it. Nobody on earth would take that as an endorsement of the candidate by the artist, just as nobody took Obama’s use of “Only in America” after his speech to mean that the Republicans who sang it were endorsing him. They played that song live for Bush in 2004. Unlike Heart, Kix Brooks only stated that he was flattered his music appealed to people in both parties.