Not sure if you're actually concerned about the cat on the car or if you were just foolin' around with this thread, but, if the former: Cats hate stepping on stuff that sticks to their feet. Get some double-stick tape and put several strips of it across the width of the top. (I'm reasonably certain it would pull off easily even after a few days
and wouldn't cause any damage.) We tell people that have problems with their cats hanging out on their kitchen counter-tops when they're not around to give this a try. It does seem to work. (And, as rick3000 suggested, if kitty decides to use the top as a scratch post, it could get ugly fast.)
How's the Pekingese rescue/transport mission progressing?