I'm not entirely sure about the motive of baby-on-board other than potentially "if there's an accident look for the baby". I don't think it's an excuse to be a bad driver but hopefully encourage people around possibly to be mindful

I've seen quite a few stickers on cars that basically state there's an autistic child/person in the car and they have a list of things the passenger may exhibit such as being non-verbal, reacting strangely, running away... Like on some houses they list occupants human and otherwise in case of emergency and people and pets need to be rescued

I understand them as= "I will drive much more defensive than most drivers. Don't be an asshole about it.*

first responders will prioritize vehicles with those stickers, specifically searching for a child first, because they are more likely to receive life threatening injuries from an accident.

don't try to scam your way into first care without a child though. paramedics and nurses talk...alot. word of mouth spreads through a hospital like a plague and you will get the bare minimum care to ensure your life is not in danger.

I’d think that if a baby is properly secured in a car, as it should always be, the driver should never risk the lives of anyone in or near that car by allowing themselves to be distracted. If there’s an emergency, with a baby or otherwise, you pull over asap.

I always took that particular bumper sticker to be some odd flex by parents, as if reproducing was some rare and impressive achievement.

They are for first responders, but all the first responders I know say they ignore them because nobody takes them off when the kid isn’t in the car.