My understanding is that the BABY ON BOARD sign is to notify emergency personnel arriving to a car accident that there is a child/baby in the vehicle who will not be able to get out of the vehicle on their own etc.
Personally, I've also looked at the BABY ON BOARD signs as a heads-up that the person driving that vehicle may be more cautious or slower than other cars. I treat it like a student driver decal.
Personally, I've also looked at the BABY ON BOARD signs as a heads-up that the person driving that vehicle may be more cautious or slower than other cars. I treat it like a student driver decal.