Other mistake: When Will Smith checks into the hotel and his credit cards are invalid, we see that the time is 5:38 and it is daylight outside. The only problem with this is that it is supposed to be around December given all the Christmas decorations. It would be dark then in the Baltimore, not soaked with daylight.
Revealing mistake: Near the end of the film, after the shootout, there's a shot with the camera zooming in on a newspaper at Will Smith's front door. If you pause it right once the headline fills the top of the screen, you'll notice all the paragraphs are just repeated, word for word. Additionally the word "received" is misspelled.
Factual error: When requesting images from the satellite, the position (latitude and longitude) is always given in degrees and minutes (but NOT seconds), and a few moments later they get a picture centered on the person they are looking for. Now a minute equals a nautical mile (or 1.85 kilometers), so with a position given in degrees and minutes you'd get a region bigger than 3 square kilometers.... which makes it impossible to find a person that fast (especially in a crowded town).
Continuity mistake: The business card given to Dan Zavitz by Bobby Dean in the lingerie shop is not the same business card removed from his pocket by the agent after he gets hit by the fire truck (second timecode). The email address along the bottom of the card has changed, In the first shot, it's 'email@example.com' and in the second it's 'firstname.lastname@example.org'. (00:25:00 - 00:26:45)
Other mistake: At the end of the film, Dean can see himself in his TV. He looks up to the fire alerter, assuming the camera filming him is up there. The film camera then also pans up to the fire alerter, indicating the camera is there, too. For this angle, the picture in the TV is wrong, as it is taken from the point of view of the TV.Christoph Galuschka
Continuity mistake: In the scene in the lingerie store Will Smith is talking to a blonde assistant. She has a piece of her hair tucked up behind her ear, but as the shot changes her hair is down loose again. When the shot changes again the piece of hair is behind her ear again. This happens roughly about 3-4 times.
Plot hole: As the characters arrive at 'the Jar', Brill informs Dean that it is entirely cut off from the outside world (no communication lines or radio waves). Yet somehow he is able to access a Government database from this very location.
Continuity mistake: In the scene where Robert Dean and Rachel Banks are having lunch in the diner, the mustard bottle is seen in two different places. It starts out to the left side of his plate, kind of behind the napkin dispenser. When she gives him the tape, it moves to the front of the dispenser. In the next shot it goes back behind.
Factual error: Satellite images only work on clear days with no clouds. But most of the days shown in the movie are cloudy which would make most of the spying impossible.
Continuity mistake: When Dean is lying down in the back of the womens station-wagon, you can clearly see the driver's neck and hair. On a close-up of the driver, you can see that there is a head-rest in the way. On return to the wide shot, the headrest has obviously been removed.