Continuity mistake: When the "Wilson sisters" and their friends are driving along during the music scene, between a wideshot and closeup the background goes from being all trees in the distance, to suddenly all the sunny sky showing, and trees changing and appearing from shot to shot.
Revealing mistake: When Marcus (dressed up like one of the sisters) is braiding the blonde girl's hair you can easily tell that the corn-rows were already done and that the hair that is not done is a wig. You can see the line were the wig starts. Also it's probably a wig because when Marcus (dressed up like one of the sisters) is braiding the hair he just looks like he is moving it and that the braids are already done.
Continuity mistake: In the scene where the homosexual fashion designer tells the two girls that they aren't in the fashion show and she offers him sex for it, he lights a cigar in his mouth. When it cuts from close-up to wide shot, the cigar moves from his mouth to his hand, beside his leg.
Continuity mistake: While Marcus and Latrell are on a date, and Kevin takes the car it is dark outside. After the scene that Marcus calls Kevin to tell them they are done eating, there is a scene showing the other two agents looking through the "Wilson's" room and it is light out. The following scene is when they are all at the club, after Marcus' and Latrell's date.
Continuity mistake: When the guys are driving the real Wilsons to their hotel, one of the guys, who is in the back, emerges from all the bags in the backseat. Between shots the bags around him constantly move, and in the first shots a brown bag jumps from behind him, to under his arm.
Other mistake: In the scene where Marcus and Kevin are first dressed up as the Wilson sisters, as they step out of the limo, Kevin (as Brittany) tells Marcus (as Tiffany) to act like a normal girl. Then Marcus flips his hair and the part in his hair is now crooked because he didn't get all of his hair back to one side. The next time you see him, the part in his hair is straight, and his hair is no longer out of place on top of his head.
Revealing mistake: When one of the 'Wilson' sisters leaves with Latrell for their date (after he starts singing to her), the car they get into is supposed to be valet delivered just before they step into it, yet when it pulls away there is a visible dry spot on the road beneath it. Clearly the car had been parked on that spot for long enough that the heat from the engine dried the wet pavement underneath it, which would take far longer than the length of one song.