Who’s Aboard?

Can someone please tell me what those mindless signs mean that I see hanging in the rear windows of cars? You know, the ones that say, “Child Aboard,” or “Baby Aboard.” What is it that I’m supposed to do when I see that . . . do I drive my car differently or what? Why not put up signs that say, “Driver Aboard,” or “Passenger Aboard,” or “Dog Aboard,” or “Groceries Aboard?”

ARON GREEN

Los Angeles