Baby on board?

On my way home today, I saw a "Baby on Board" sign on the station wagon driving in front of me. And I wondered: Does that really make anyone more cautious? Perhaps, in this age if litigiousness, people would be far more cautious around a car that had a sign proclaiming "Lawyer on Board." For while lawyers are a loathed group of folks, the consequences of careening into a lawyer could prove far more dire.