Visible crew/equipment: The reflection of a large light used to light the shot is visible in the car window as Wayne is driving away after dropping Kevin off at the mall.
Odd Man Out - S3-E6
Factual error: Near the end of the episode when Kevin and Paul are riding their bikes toward each other before they stop for a brief hello of sorts, Kevin rides past a couple cars parked on the street that were built in the early 1980's. A red Pontiac LeMans and a black Pontiac Grand Prix-both were parked in front of the 1969 Ford Thunderbird.
Factual error: After the failure to get a new car, the family is sitting around disconsolately watching TV, when a commercial for a new Camaro comes on. However, the Camaro shown is a second generation unit, not introduced until February of 1970, and the Arnolds are still stuck in 1969.
Continuity mistake: Back when Ms. White said that she was going to get married over the summer, she should afterwards be called Mrs. Hiemer, as she wrote on the board. But in this episode, we're shown a yearbook, and her name is printed as Mrs. D. Hymer.
