Go to the middle of the movie when Mary-Kate has been kidnapped along with four other people. Ashley and Brian (I think) go to rescue them, right? Well, after they have helped the people out of the room, and they are going through the air ducts, they all go one way except for Brian, who goes left. Then he ends up sliding down, saying he found a short cut. Well, after him, Ashley goes, or at least Ashley is supposed to go down. Except, if you pause it while she is sliding down, it is clearly Mary-Kate. In this movie, Ashley has long hair, but when she is sliding down the air duct, her hair is short, and you can tell that it is Mary-Kate's face. Watch it and see. I have watched it many times, and it is definitly a slip-up.