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 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: When the 4 humans rush out of the pool house, there are 3 aliens not dressed in their human skins watching them leave. The problem is: only one alien has eyes. We've seen the aliens out of their skins heaps of times and they always have eyes.
Other mistake: The posters and DVD / Blu-ray covers with Billie Jean are different. Her lone earring's on her right ear when in the movie it was on her left ear. Her bangs are combed to the left instead of right and her armband's on her upper left arm instead of her upper right arm.
Suggested correction: Something being different on the poster or DVD cover is not a movie mistake.
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.