Just so people aren’t misled - ASCAP is a not-for-profit, it isn’t a government agency. I think a more accurate word for it is “cabal” since most people don’t know much about them and that they often work against (IMO) the public interest.

I meant that someone can't assert copyright over your live performance of your own compositions as it occurs. Copyright can be asserted over a recording of course. Someone might try to assert copyright over portions of the music I suppose. In this context though there's no way for copyright to be valid unless he's assigned the copyright to someone else which doesn't seem to be the case barring any further information.