While preparing a meal in the beginning of the movie, Jane is talking to a client on the phone. Billy is on her shoulders, holding the phone to her ear. Dick says "Fire", and Jane turns to tend to a fire on the stove. A second later in front of the stove, Billy is no longer on her shoulders and Jane is holding the phone herself.
While teaching the aerobics class, there is no sweat on Jane's shirt, in the next shot there is, and in the shot after, it's gone.
While Dick's former colleague is climbing the stairs, trying to beat Dick for a job interview, he carries a briefcase. By the time he reaches the floor he has an attaché type case instead.
The shot of Jack signing Dick's check in the Grand Cayman Bank is dated in October 2000. When Dick holds the check up, it is dated February 20th. The year is now crossed out.
When Dick runs out of the convenience store from which he "stole" the Icee, the original clerk is sitting behind the counter, but he had been told to step aside by his much larger associate, who is not visible.
Frank explains to Dick that they made the balance sheet show profits when there was only debts. Profits aren't shown on a balance sheet, but on a profit and loss statement.
In the Grand Cayman Bank scene there is a brief shot of the Client Relations Cooridinator's business card. On it are two numbers, one of them a phone number, and the other for "facimile". It should read "facsimile."
When the Harpers have a new lawn installed, the shadows cast by the house do not move although the accelerated scene is too long for the sun to have remained stationary.
While Dick and Jane are robbing the coffee shop, it seems that all the customers "disappear" after they are finished robbing it. However, for a brief moment, all the customers can be seen moving to hide under the tables.
The squirt gun is painted in pure black. All toy weapons have an orange marker to indicate (especially to law enforcement) that they are not real deadly weapons. But it is possible that Dick may have painted it before bringing it in front of Jane, to make it appear more like a real gun.
When Dick and Jane are in the hole in their yard, they said that the electricity was shut off but when the nanny comes out you can see that the lights are on in the house.
After leaving the head shop in the rain, the hose making the rain is visible.
The Grand Cayman Bank has no visible security cameras.
The Nissan XTerra parked in the Harpers' driveway is a 2002-2004 model. The movie is set in 2000.
The rolls of Brawny paper towels visible in the convenience store have the newer version of the lumberjack figure that first appeared in 2003. The film is set in 2000.
At the very end of the movie, when Dick and Jane are going for a drive in their car, the cameraman is reflected in Dick's sunglasses after he talks to his friend one car over.
It has been illegal to issue municipal or corporate bearer bonds since 1982. McCallister wouldn't have been able to convert his company's assets into bearer bonds.
When Dick is watching his wife sleep, just before he steals the grass from other yards. The camera shows his head, and you can see the shadow of the boom mic.
In a scene in their bedroom while yelling, Dick calls Jane by Téa (her real name) rather than Jane (her movie name).