Deliberate mistake: When the two girls have get into the limo for the first time with the fake Chinese guy and they realized that they are now trapped and being taken away, there is a shot of one of the girls through the limo's window, limo windows aren't clear they are tinted so we shouldn't have been able to see her face.
Continuity mistake: When Roxy fights the fake Chinese guy with her drumsticks in the subway station, Jane and Roxy end the fight by grabbing his coat/jacket and pulling it over his head, then shoving him into a subway car. When they first shove him, the jacket is over his head. When he is stumbling in, it is suddenly nice and neat, down in its proper position. But the in the next shot of him hitting the seats, it's back over his head as he struggles with it.
Other mistake: When the twins and the dog are on the trashcan, they all move down the side of the trashcan, even the dog. IT really couldn't happen the way it did because dogs can't walk very smoothly on their hind legs especially when their hind legs probably are dangling in mid air.
Factual error: When the band (Simple Plan) is playing, the name "Lomax" is repeated by many people, including Simple Plan's drummer (Chuck Comeau), however, while playing the drum set, it is hard to pay attention to almost anything besides what you are doing without messing up on the song.