The gang checks in to a haunted hotel where a Sneaky Sandman is robbing guests and scaring them away. They are visited by the Sneaky Sandman on the first night and they are robbed while having their nightmares. Fred uses Scooby and Shaggy as bait and discover that the bell hop and a rival hotel owner from across the street are portraying this haunting in order to run the hotel out of business.
In the next story, I'm asked to accept that the crooks are so bent on their real estate scheme that they are willing to use expensive, scifi tech from The Prisoner to better make their victims susceptible to the costumes representing their greatest fears. These costumes just happen to be lying around. How is this possible! Bad dog! Bad!
I know that some people are laughing and saying "This is Scooby-Doo, dude. Lighten up." Why shouldn't Scooby-Doo be held to the same standard I apply to say a Batman book? A story no matter the target audience must have appealing characters. A story no matter the target audience must have structure. A story no matter the target audience must make sense. It's that simple.