Revealing mistake: When the underwater camera breaks the surface in what is supposed to be open ocean, the domed roof of a Hawaiian aquatic theme park building is visible in the background.
Come In, Your Time Is Up - S8-E4
Revealing mistake: In the very first scene Captain Mainwaring and Sergeant Wilson cast multiple shadows despite supposedly being in bright sunshine.
Revealing mistake: Lori Chan picks Mundy up at the airport and proceeds to speed through town, spinning the steering wheel left, right and left again repeatedly. But the rear-screen projection behind them is showing footage from a car moving steadily in a straight line. (00:07:45)
Revealing mistake: When Stemple and Jason argue on the porch, an electric light bulb is very apparent in the lantern beside the door. (00:41:00)
Revealing mistake: Halfway through the show, the officers get a flat. As Malloy is getting ready to jack up the car, Reed starts using the lug nut wrench to loosen up the nuts. He repeatedly turns the wrench clockwise, which would tighten the nuts.
Aunt Bee's Cruise: Part 1 - S1-E15
Revealing mistake: Aunt Bee is traveling on a cruise ship. The "water" in the background is a painted backdrop which is made all the more obvious by the painted whitecaps.