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.
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.
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)
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: When they are going to kill the senator, the killer walks on one side of the dog, but when you look at the tape one of the guys has, the killer walks on the other side of the dog.
Factual error: While escaping from thugs in Hackman's pickup, Smith points a sawed-off shotgun in front Hackman's face and fires at the baddies. Hackman should have been deaf, but he didn't even blink.
Continuity mistake: When Brill blows up his hideout, he is in his truck with Robert. In the background, the building collapses. The shot changes, then the next shot is of the same building collapsing, but from a different angle, even though the building has already collapsed.
Other mistake: When Daniel Zavitz realizes that his video contains the murder of the Congressman he plays it several times showing the portion when the man attacks the Congressman. The Congressman opens his car door and then closes it before he is even attacked.
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.
Other mistake: In the scene where Fiedler is looking up Robert Dean and Rachel Banks' college history, both Dean and Banks' student numbers are the same.