Deliberate mistake: The little red-haired girl boards a bus with other children who are headed to summer camp. As the bus drives away, there is nobody in the driver's seat. This movie maintains Charles Schulz's policy of never showing adults in his comic strips or animated television specials, but a bus driver could at least have been depicted in silhouette.
Deliberate mistake: The snacks in the vending machine were almost to the top of each display shelf, but an interior to exterior view showed the lab researcher's head unobstructed and a foot or so clearance between the snacks and the top of the shelf. (00:06:30)