Directed by: Mark Waters, Mark S. Waters
Starring: Rachel McAdams, Amanda Seyfried, Lindsay Lohan, Tina Fey, Lizzy Caplan, Lacey Chabert, Jonathan Bennett, Neil Flynn, Tim Meadows, Daniel Franzese
Factual error: The mall that the plastics state they are going to, Old Orchard as stated by Cady, is an outside mall. However, the mall they go to is an indoor mall.
Factual error: While the plastics are at the mall there is a Bell Mobility booth seen behind them. This booth wouldn't be found in an American mall as they only service Canada.
Continuity mistake: After the Halloween party, when Cady walks into Damian and Janis' house, Damian gets scared and tosses all of the popcorn out of his bowl. In the next shot of Damian his bowl is full again. (00:29:05)
Trivia: Tim Meadows, who plays Mr. Duvall, broke his wrist a week before filming started and had to wear a cast. They explained this away in the movie by saying that Mr. Duvall had carpal tunnel syndrome.
Question: After Cady sends a candy cane note to herself, pretending that it came from Regina, Gretchen says that Regina does not even like Cady very much. So why is Regina still allowing Cady to associate with The Plastics? As the "queen bee", she could probably decide to ban Cady from the group.
Answer: I think Regina secretly felt threatened by Cady. Janice and Damien comment about Cady being "a regulation hottie." She is attractive and has the "exotic" appeal of being a new student, plus she is new to traditional school in general, having spent many years in Africa. Regina guessed that Cady would have this exotic appeal. Pretending to be her friend was better than competing with her. It's a "keep your friends close and your enemies closer" tactic.
Answer: Regina enjoys manipulating people, and she views Cady as a relatively easy person to manipulate, finding her more useful/amusing to keep in their circle. It's a running theme of the film that the friendships between all of the Plastics is very tenuous, because of the catty, manipulative nature of the girls.
Purple_Girl
Also, if Regina tried to ban Cady, people might think she was threatened by Cady. Better to keep Cady around and attack her in subtle, manipulative ways.