I know the guy with the 928 with a "My other car's a Porsche" sticker - he used to race another 928 in the Porsche Cup. Mad
...
One that made me smile was a Motorcycle News sticker that said "My other car does wheelies..."
The only remotely sensible explanation I've ever heard for the "Baby on board" signs is so emergency crews know to look for/rescue the child in an RTA. Of course that would only work if the parents took the sign out of the car when the baby
isn't on board...
Unless of course it means
"I'm a parent so I've had a frontal labotomy and will almost certainly do something completely irrational right in front of you..." 