The scene where Lulu tells Shane that she thinks he's cute and Shane's embarrassed response was based on a real-life incident on set. Morgan York (the actress who plays Lulu), upon meeting Vin Diesel, actually said that to him and he awkwardly responded with a "thank you". The director thought it was so funny that he put it in the film.

They had to shine a red light at Vin Diesel's ear to get the duck to bite it.

Originally, Jackie Chan was attached to this film. The ninjas in the movie are from his stunt team. Ironically, Jackie Chan would later appear in The Spy Next Door (2010) which has a similar premise to this film.

Boo Berries cereal is not sold in Canada. Adam Shankman's assistant had to drive to Buffalo, New York to get it.

The idea of the family having a pet duck was introduced by Thomas Lennon and Robert Ben Garant when their script had Jackie Chan attached. The running joke was that Chan's plan to kill the duck and cook it for dinner horrified the kids, and therefore Chan ended up reluctantly keeping and taking care of the pet. Even when Chan exited the project and other writers worked on the script, the duck stayed all the way through to the finished film.

Continuity

When Shane Wolfe is setting up wires on a pole at the Plummer house, it is raining, but there is no sign of rain before or after that shot.

When Shane and Murney are fighting in the gym, Shane first has got Murney's left arm blocked. In the following shoot, Shane has Murney's right arm blocked.

As the director gives his lecture about their imminent opening, the shot cuts to the woman Seth dropped, and you can see the mountain prop is already broken, yet in the next shot, it is intact.

When Shane is fighting the Ninjas upstairs, a Ninja runs up behind him and falls for no apparent reason, but in the very next scene the same Ninja runs up behind him again, only this time the Ninja falls because Shane has used his feet to spin a broom handle around, tripping the Ninja.

When Shane and the Fireflies enter the kids play area, you can see a mother try to pull her kid out of a ride. In the next shot, we see the same mother and child walking behind them, but when we cut back to the play area, the mother is still trying to get the kid back out of the ride.



Factual errors

The Montgomery County Police Department are wearing blue uniforms in the movie. However, in 2005, the MCPD wore khaki uniforms.

In the end scene when Captain Fawcett and the North Koreans are being arrested they are being arrested by the FBI. However, as Captain Fawcett is in the Navy and the case is related to the navy, then NCIS would've been the federal agency involved in the arrest.

When the family and Shane Wolfe are in the arcade you can see an Mortal Kombat 2 machine, later when Shane is getting the kid out of the balls you can see the screen on the MK2 machine and it shows the text and logo for Mortal Kombat Trilogy, which was only released on home consoles and was never in the arcades.



Incorrectly regarded as goofs

When Seth heads upstairs to the bathroom when Shane is handing out the tracking bracelets, he is barefoot, and when he exits the bathroom, he is wearing socks. However, he is upstairs about two minutes, giving him plenty of time to put on socks.

When Lt. Wolfe discovers that Seth has gone out the window he tells Zoe to watch everyone and to alert him if anyone comes within 40 clicks of the perimeter. 'Klicks' is military jargon for kilometer so in reality he's telling her to warn him if anyone comes within 40 kilometers of the house.



Revealing mistakes

When Mr. Chung jumps through the window in the children's bedroom, he clearly uses no force to break through the entire pane.

When Shane is attacked by the ninjas in the upstairs hallway. he blocks one of the baton strikes with his forearm. The baton bends from the block clearly showing the baton is not made of metal but rubber or some sort of other safety material.



Anachronisms

In the party scene, Shane is clearly seen wearing a Hanes tag-less v-neck shirt. This model of the shirt did not come out until after the date the movie was set.



Audio/visual unsynchronized

When Shane is using the Peter Panda Dance to get past the security to the program Ghost, he steps back one step to avoid a blade that comes down in front of him. You hear him say, "One step back," but his lips don't move.

When Shane is asking for help while changing the baby, he says, "Guys..." when his lips appear to say, "Come on," or something like that.



Crew or equipment visible

When Shane jumps into the sewage to retrieve the bracelet, a camera is visible on the right side of the screen. May not be visible in the pan and scan version.



Errors in geography

The movie is set in the USA, but there are signs for the TTC (the Toronto public transportation system).

The US Government car used in the last car chase has a speedometer where the large numbers are in kilometers per hour, and the small ones in MPH, consistent with this film actually being filmed in Canada but not correct for a US Government car.

The film is set in Washington, D.C. and Maryland, but Winners - a Canadian store chain with no outlets in the United States - is visible.



Boom mic visible

When Shane investigates Lulu's scream on his first night, and he walks in to find her playing a video game, a boom mic is reflected in the windows behind them.



Character error

When the Navy SEALs are addressed, they are referred to as soldiers. This is incorrect as SEALs are navy sailors, and are addressed as such.

Classified information can never be viewed outside of a cleared area - especially not in public, as when Shane looks up information on the housekeeper while in the home, or when he looks up information about the principal while out on the playground. This would be considered a serious security breach.

When the Junior Grizzlies harass the cookie-selling Firefly troop, the leader says "This is troop sixteen territory" but the troop numbers on his sleeve clearly are a 3-digit number ending in 15.

In accordance with U.S. Armed Forces dress code, a plain white t-shirt is considered as 'underwear'. Due to this, Shane, a strongly devoted serviceman, would not wear one as an actual shirt if he were in the military.

Shane continuously refers to Fletcher as outranking him, but Shane is a Lieutenant while Fletcher is a Petty Officer Third Class. He outranks her by leagues.