Continuity mistake: When Fred, Velma, Shaggy and Scooby discover that Daphne has fallen through the trap door, look at Shaggy and there is nothing on the wall, but when we see Shaggy scared by the ghost, a shield has suddenly appeared.
Continuity mistake: When the ham sandwich floats down in front of Shaggy, the sandwich has lettuce in the middle. When we see the sandwich on the table, the lettuce has gone.
Continuity mistake: After Scooby reads "Danger - Leave Haunted Isle" on the back of the map which Fred is looking at, he turns the map around and on the front there is an outline of an island. In the next shot, the outline has disappeared.
Continuity mistake: When Daphne is holding the large key, the rims on her cuffs are violet, but in a close-up, they are white.
Continuity mistake: When Fred is holding the map that Scooby found, he is initially looking at the back, but in the next shot, it has suddenly turned correctly.
Continuity mistake: In a close-up of Scooby and Velma on the boat, the spots on Scooby's back are missing.
Continuity mistake: When we first see a close-up of the gang on the boat, the pleats on Velma's skirt are missing.
Mine Your Own Business - S1-E4
Continuity mistake: When Fred says that "I have a hunch that he'll turn up soon", there is a tape recorder on the desk and Daphne and Fred are standing in front of it, but in a close-up of the recorder, Daphne and Fred have gone.
Mine Your Own Business - S1-E4
Continuity mistake: When Scooby and Shaggy are standing at the closet doors, the door where is Shaggy is standing has the knob on the right hand side, but when the two swap places, Scooby opens the door and the knob is on the left hand side.
Mine Your Own Business - S1-E4
Continuity mistake: When Fred takes the map out of the body of the cigar store Indian, he is holding it with one hand, but in the next shot he is holding the map with both hands.
Mine Your Own Business - S1-E4
Continuity mistake: When Shaggy pushes Scooby into the abandoned hotel, there are two spots on Scooby's back, but after a quick cut to the gang standing outside the doorway, we return to Scooby and the two spots have disappeared.
Mine Your Own Business - S1-E4
Continuity mistake: When the gang opens the safe inside the old hotel, revealing the secret elevator, they are standing inside a large lobby, but when Daphne is attempting to coax into the elevator with Scooby Snacks, the lobby has gone and is now replaced by a wall.
Mine Your Own Business - S1-E4
Continuity mistake: Velma initially has nothing on her lips during the scene where Hank is showing the gang their rooms, but when Hank says "The Miner Forty-Niner", we cut back to Velma and Daphne and lipstick has now appeared on Velma's lips.
Mine Your Own Business - S1-E4
Continuity mistake: When Hank is showing the gang their rooms, Scooby has two dots on his back, one large and one small. Later on during the scene, the small dot has decreased in size.
Mine Your Own Business - S1-E4
Continuity mistake: When Fred asks Big Ben if he has any rooms available for the night, Daphne's eyes are drawn higher, drawn underneath her bangs, making her look off-model.
Mine Your Own Business - S1-E4
Continuity mistake: When Big Ben opens the door of the Gold City Guest Ranch, the door is red, but when we see Big Ben holding the door in the next shot, the door is now dark brown.
Mine Your Own Business - S1-E4
Continuity mistake: Daphne's scarf is green when she is sitting in the Mystery Machine, but when she with the gang at the entrance of the Gold City Guest Ranch, her scarf is now purple.
Mine Your Own Business - S1-E4
Continuity mistake: In a shot of the Mystery Machine driving through the Ghost Town, Shaggy is looking out of the window, but inside the machine, he is now looking at Fred.
Mine Your Own Business - S1-E4
Continuity mistake: When Scooby sees a man behind the door he has opened, the door knob has a lock, but when Shaggy opens the door and sees nothing, the lock is missing.
Mine Your Own Business - S1-E4
Continuity mistake: When Scooby pulls off the boots and falls down below, the stilts are short, but a couple of shots later they are longer.
Chosen answer: A ghost wouldn't have to keep any food in the fridge - they don't need to eat. So it is one thing that proves the ghost is not a ghost.