This slip-up happens in the 7th season, in the episode where Rudy babysits Olivia. The two decide to sleep in Clair and Cliff's because they were frightened by the scary video. Rudy comes into the room and tells Olivia that she turned off all the lights in the house and set booby traps. Then the kids go to sleep. When Clair and Cliff get home, the lights in the living room are turned on, even after Rudy said she shut off all the lights. Clair and Cliff did not turn them on, they were already on when they opened the door.