When Billy Ray is in the limo, Randolph Duke introduces himself and Billy Ray asks if the name Randolph is like Randy Jackson of the Jackson 5. Randy was not a member of the Jackson 5. He did not join the group until they became The Jacksons.
When Mortimer Duke is signing the paychecks, at least one of the shots is flipped horizontally. At first he signs with his left hand, then his right, then his left again. The part in his hair changes sides as well.
After Valentine is challenged by the police officers and finally walks away, the camera cuts several times between him and them. The direction towards which he is walking, as shown by the houses in the background, switches back and forth a couple of times.
On Valentine's 'first day on the job,' he enters the Dukes office and the sound of a door closing is heard after he enters, but the chase shot (behind Valentine) reveals the door to still be open, yet in the next shot, from the opposite side of the room, the door is closed.
In the first scene, Louis is going to work, you can see the streets, no snow at all. Later the same day, the Dukes are going to work and as you can see there is plenty of snow. Even later when Billy appears first in the park, plenty of snow.
When we first see the Dukes going to work, in the car Mortimer is sitting on the left hand side of the car & Randolph on the right, but when they arrive at work Randolph gets out of the car first on the left.
In the park after the 2 cops expose Billy Ray, the cop on the right is standing with his legs slightly apart facing the camera. The shot from behind shows him standing with his hips to the right, one leg behind the other.
The Dukes park their limo on Locust Street heading west right before Billy Ray appears. Locust Street is one way heading east and all other times in the movie we see the cars heading east on Locust Street.
When Louis is in the bank, he asks to withdraw $500, continues writing the slip, then changes his mind, to $1000, then tears off the slip. Most people enter the figure first. Louis would have amended the figure but his body language doesn't show this.
On the train from Washington to New York, the sound of the train passing railroad crossings is heard several times. Due to the speed of the Amtrak Northeast Corridor line, there are no railroad crossings like that.
Winthorpe's car, a Mercedes Benz 600 Grosser - is unique in that it features a complex hydraulic system that runs everything from the windows to the suspension. The car would need time to run and generate enough hydraulic pressure for the suspension to raise the car to proper operating height. It would not be possible for Coleman to just start the car and drive to work as is done in the beginning of the movie.
When Winthorpe is in the cab and Valentine is in the limo and they see each other, the street they are on, outside Independence Hall, is two-way traffic. This was only done for the movie. In real life, this is a one way street heading east. You can see the white lines on the street dividing the travel lanes, rather than a double yellow line which would be needed for it to be denoted as a two-way street.
At the Christmas party when Winthorpe jumps on the table waving the gun, the clocks show that it is 1905 in Los Angeles, 2205 in Philadelphia and 0205 in London. London should read 0305. London is five hours, not four, ahead of Philadelphia, regardless whether in Daylight Savings Time (British Summer Time) or in Standard Time.
In the large room when framing Louis, everyone is instructed to place the contents of the jacket pocket of the person to their right on the table. The people lining the walls have no such tables. The people on the right end have nobody emptying their left pockets.
When the members of the club are asked to dig inside the pocket of the man to their right and to put the content in front of them, the row of members in the back of the room do not have any table or any support on where to put said content, as they are only sitting on chairs.
During early scenes in the movie there's a fair amount of snow on the ground, but later scenes show a completely dry and snow-free Philadelphia. In fact, one overhead shot of Constitution Hall and the surrounding park shows green grass and leaves on the trees - highly unlikely in Philadelphia at Christmas time.
When Louis is walking past the restaurant in the rain, the scene switches to him a number of times and you can hear the hard rain falling. The first time the camera shows a close up of Louis however, the camera is still inside the restaurant yet the sound of rain falling is heard, drowning out the crowd noises in the restaurant that are heard continuously (other than when Valentine is making his prediction about the Russian wheat crop) when the camera is inside.
The road in which Winthorpe and Valentine meet in the taxi and limousine is delineated by a white line. Yellow lines are always used to delineate opposing lanes, while solid white lines delineate the right edge of a traffic lane, and sometimes lanes going in the same direction.