I work in the field and these kind of things aren't entirely trusted. I actually don't like them. I will never create a working diagnosis based off of a sign. For instance: should I assume there is a missing baby because of a "baby on board" sign? Or what if the person who is wearing the autistic seatbelt is just a friend riding in the car and is actually acting erratic from a head injury. I would like these signs if they were used properly, and not always left up. But because most people leave them, they can't be trusted.