I'm not a musician, though I can play a little blues piano. In my experience you don't have to be a musician to be able to hear the structure of choruses, recognize changes, anticipate phrases - in short, know where the music is going. That said, I realize that many - perhaps the majority - of the audience members at gigs I go to don't even have this rudimentary knowledge. I was somewhat amazed when Greg Abate said that he'd failed to teach a prolific organizer of gigs in these parts to recognize when a chorus ended and another began!