Other mistake: After the Griswolds leave the German couple's house, the man says "Who the hell were they?", and the woman says "Beats the shit out of me." However, since they slept there overnight, they had enough time to discuss it in private much earlier.
Other mistake: A long-nailed woman types the opening credits in a computer, but in a couple of instances (the Playboy Playmates, for example) you can see her type away when the credits page is already complete and the names are already there. (00:01:00)
Other mistake: After Wendy reads the fake note she wrote from 'Snookie' to 'Bubbles' she tells the guys that it's really Peewee who is being set up to meet at the motel with Ballbreaker (Bubbles). Yet it's Tommy who shows up at the door.
Suggested correction: That's because Tommy conned PeeWee into giving him the candy and flowers, then sent him back to his room for something else in place of those. Then he ran of, got into his vehicle, and sped away. That's why when PeeWee showed up, and they asked who was in the room, he said "Tommy" as he realised Tommy duped him.