Other mistake: When Zach is watching Laney at the show, there are two shots where Laney, Mitch and the little people say, "Be silent, be still". In the first, Mitch's legs are far apart and on the ground, and in the second shot his legs are very close together, with no time to move. (00:22:35)
Continuity mistake: When Zach is talking to Mackenzie about Laney (right after it shows Brock farting on 'The Real World'), there are two shots. In the first, Mackenzie puts cream in her hair, and right away there's another shot but it shows her putting her eye makeup on. She couldn't have finished putting the cream in her hair so fast. (00:14:35)
Continuity mistake: In various scenes before Rachael Leigh Cook cuts her hair, it's very obvious she's got hair extensions in - there's a noticeable line where they join. Can't be that her character has them - she'd never bother artificially lengthening her hair.
Continuity mistake: At the beach when Zach and Laney are leaving it is sunset. In the next scene at Laney's house it is mid afternoon at the latest. It has to be the same day because they attend a party that is mentioned as "tonight".
Continuity mistake: When Laney says "who the hell would nominate me" when she reads the flyer her hair is tucked behind her ear in a close up shot, yet in the next shot further away you can see her hair is now over her face before she puts her hand up to tuck it away.
Other mistake: When Laney goes to the beach she's carrying a huge book. When they leave the beach, there's no book.
Answer: The appearance was a cameo only. It was not that random though, as the scene was shot at a location also used for Buffy The Vampire Slayer, and Sarah Michelle Gellar's husband appears in the movie.
pinkwafer