Ought to be Illegal!

I was driving through town when I saw a blue light flash ahead in the distance. Emergency vehicle, I thought to myself and watched alertly for more flashes. There was no more blue, but soon I saw a yellow flash ahead. Then an orange flash. By now I knew which car it was, and I looked carefully as we passed. It had a CD hung from the inside mirror, turning lazily annd reflecting sunlight in all directions. That Ought to be Illegal!