Wow! You know, I never knew that. It sort of nagged at the back of my mind for lo these many (?) years, now and then. Hey, it's a normal explanation after all! Thanks. :)

I wondered why they didn't pick a good one out of them, but the VCA Instrumental winner for 2005 was an opening-credits parody that, while excellent, wouldn't have translated outside the fandom. So... that makes sense.