In the episode, "The Case of the Marine Bandit", did Betty Ann drive an Austin Healey 3000? In the episode, Gomer says "too bad there isn't a back seat" to Sgt. Carter. When I was in high school, my friend Mark's dad had a 3000 and there was a small two-seat rear seat. I guess they needed a reason that she could only take one Marine.

It is hard to imagine Grandma Walton as a criminal.