On its face that sounds like a really stupid idea, but it could lead to some pretty unusual combinations. You could have the player cue up I'm Too Sexy when you actually undo the zipper, or perhaps the Stones' She's So Cold if the zipper is pulled to the top.

Zip jacket controls your music based on your state of dress - Electricfoxy - jacket

Zip jacket controls your music based on your state of dress - Electricfoxy - jacket