I like the idea but the administration (finding a band, combing through their song list) would kill me... but if you could pull it off, it would be mighty leet.
Like that post's idea of the sum of the whole coming together in some inadverdent way - the red herring could be the newest band member to join, but really it was that addition that did it.
Perhaps one of them has bought a vintage instrument recently that channels power.
Maybe its the slightly tweaked logo that they have now.
Perhaps the singer adlibs on the fly but the band is so raw that nobody really notices or cares, and just assumes he's screaming out something on the spot, not realizing that he's really in a trance and that some oracular spirit has taken over his body and is dispensing divine truth.
It'd be cool too if that advice isn't general but is aimed at somebody in the crowd - somebody who knows that this power is happening is actually in the front row, shouting questions at the singer and getting their answers.
What if they aren't the only ones? What if a prog trance DJ is spinning medleys whose titles put some kind of message out?
That folk fiddler on the corner is throwing together reel sets that haven't been heard for a hundred years?
That child prodigy who was supposed to perform a Rachmaninoff at the Performing Centre feels compelled to play the a Hungarian folk dance that he hears everywhere, and he's hearing snippets of it from DJ's, folk fiddlers, that punk band that's opening next week... and it all weaves a tapestry that's directed by somebody, someone, somewhere, for some purpose...
Anyways. Off the top of my head. Hopefully some are helpful...