I'm tempted to criticize those parents for their negligence, but pride comes before the fall. I know from experience that one three-year-old can be enough of a challenge to keep track of, 18 bags and four other kids aside. Still, I've gotta admit it doesn't reflect well on the parents that they had to be "informed" of their mistake. I hope that if I ever left a kid behind, I'd realize the mistake myself, and quickly.