Continuity mistake: When all of the politician's 'henchmen' are leaving 'the office' one of them is wearing sunglasses, that he did not previously have on in that scene.
Continuity mistake: In the beginning scene with Jason Robards and Jon Voight talking on the bench, there seems to be a difference in temperature between shots. When there is a close up of Jon Voight, you can see his breath in the cold air. When there is a close up of Jason Robards, no breath is visible at all.
Character mistake: After the Congressman is killed, the killer dumps pills on the floor of the car. Then the car is then rolled into the river. At about 15:07 the news reporter mentions that the Congressman's heart pills were found in his lap. This would be impossible because the pills and bottle would float and the pills would dissolve in the water. (00:03:45 - 00:15:05)
Continuity mistake: When Dean is on the 17th floor, running from the NSA guys in the hotel, Mr. Wu's room number is 1721. But the NSA guys radio they're at room 1712, and it ends up being the one Dean and the Wus are in.
Factual error: After Will Smith escapes the ambulance and runs into the transit tunnel, NSA crew tunes to the frequency 7.210 Mhz as indicated by a piece of tape stating that is the City authority frequency. Trouble is twofold. First that frequency is an Amateur Radio (Ham Radio) frequency, only for use by licensed amateurs, and second all municipalities and local organizations use VHF frequencies and higher due to propagation and the antenna lengths involved in order to talk to mobiles and vehicles. The frequency should have been above 150 Mhz to be accurate.
Other mistake: When Bobby give Daniel his business card, he was running for his life out of the store. but when they found the business card and Daniel, it was tucked into his leather jacket pocket. Daniel wouldn't have taken the time while he was running to put it in his breast jacket pocket, because when you see him running in the street, and riding on the bike his hands are busy. (00:28:00)
Continuity mistake: While in the burning car, we see the fire engulf Robert Dean's arm, up to the shoulder, as well as in his lap. But during shots from outside the car, there's no sign of him being engulfed in flames. Then in the last shot, his jacket is back on fire, but not as much.
Continuity mistake: At the Reynolds' residence, when Tom walks into the bedroom, his wife's hand is on her chin. In the close up shot of her asking if anything is wrong, her hand is no longer there and her arm is down, then in the next shot, her hand is back on her chin.
Continuity mistake: When Will Smith first escapes the ambulance he runs down a tunnel. There is little or no traffic, but when when the agents are closing in on the truck with the power washer, it is jammed nose to tail. Where did all the traffic come from? It wasn't busy enough to create such a small bottle neck of a traffic jam.
Factual error: When the NSA people identify Brill and go through his file, they tell us that he graduated from Drexel University in 1964. Brill could not have graduated from Drexel University (DU) in 1964 because it was called Drexel Institute of Technology (DIT) at that time, which is the name that would be in the official file. It didn't change from DIT to DU until 1970.