I see these signs on car windows all of the time and I wonder if people are more cautious because their is a dog, child, or elderly person in the car. Personally I try to be cautious of other cars no matter who is in the car. I do think that the person who came up with those signs had a good idea and has made a bit of money.
Caution Puppies at Play
and another playtime video
We are looking for a guardian home for one of these puppies on 1/29/17
Ashford Manor Labradoodles
Australian Labradoodle Breeder