During Olive's routine at the pageant, at the start of the heckling, Frank stands up in the audience to clap and support her, and remains standing. Moments later there is a close-up of Sheryl, still seated, and you can see Frank's shoulder on her left, and he's still seated.
When Frank turns the TV on in the motel to try and prevent Dwayne listening to his parents arguing in the next room, President George W. Bush is shown on the TV making a speech. The clip in question is all taken from one sentence of an August 24th, 2001 speech announcing the nomination of Air Force General Richard Myers for the chairmanship of the Joint Chiefs of Staff. The clip starts in the middle of the sentence, but as camera angles change it jumps first back to the start of the sentence, and then to almost the end of the sentence. To add further confusion, while this clip suggests the film to be set in 2001, near the end of the movie we see a New York Times Book Review cover listing a June 2005 article, "The Passions of Robert Lowell" - making it unusual for an almost four year old speech to be on television.
The uneven participation of the girls during the pageant makes no sense; they seem to mix and match various girls, but all of them do not seem to be present at all events. For instance you never see the first two girls presented on stage again for the remainder of the program. The host says there are twelve girls in the competition, but after the initial introduction, the catwalk routine, you see only six girls in a row on stage, all about the same age/height. They start on one end, and after only two girls' participation, they jump immediately to Olive on the opposite end. Seconds later, after Olive finishes, you see all twelve contestants on stage. During the talent competition, we see new girls never initially shown at the introduction. And why are so many girls, non-participants, dressed up as though ready to compete, in the audience?
In the first scene in the van, Olive isn't wearing her glasses. Although a viewer could easily say she took them off so her headphone wouldn't make them dig into her head, this was actually a mistake that the directors didn't notice for a very long time.
When Olive and her mom are in the dressing room, we see one little girl wearing a 2-piece suit walking in the background. A few seconds later, the same little girl is walking outside in the hallway in front of Dwayne, wearing a dress.
In the first dinner scene, when Olive is talking about Little Miss Chili Pepper, the bottle of Sprite is at the edge of the table, beside the red cup and Olive, in the next shot, the bottle is in the middle of the table.
When Frank is at the gas station and he starts talking to his former grad student, the pile of magazines he's buying change order. In the shots where Frank is trying stand in front of the clerk and the magazines, the blue on with the men is on top. But in the close-ups we (and the grad student) see that the white magazine with the women is on top.
When Olive is testing Dwayne's vision, she is holding the color-blindness pamphlet test, which Dwayne takes away. In the next shot, he is holding the test, but when the camera goes back to Olive, she is still holding the pamphlet.
When Sheryl is backstage with Olive before going on for the talent competition, the little girl who does the Navy-style dance is seen being primped in the background. When Dwayne is seen running down the corridor to prevent Olive from going on, the same little girl is seen walking through the hallway. When the scene cuts back to Sheryl and Olive, the little girl is still there.
In the scenes following where Dwayne escapes the VW bus and runs downhill into the field, the position of the bus changes. First it is on grass near the edge of the descent, then, in the front shot it is parked neatly at the curb on the roadway. If the VW bus was parked at the curb, then from the low shot taken from Dwayne's position in the field we should not be able to see the lower portion of the wheels, but we do.
When Dwayne is sitting in the field the clouds appear and disappear. When he first sits down, the sky is full of wispy clouds, but when the scene cuts to the rest of the family at the top of the hill the clouds are gone. When it cuts back to Dwayne, the clouds are back.
In the Hotel scene, when we first see the birds eye view of Dwayne, his hands are crossed over the word "Jesus" on his shirt. In the next shot of him, he hasn't moved, but the words on his shirt have shifted up above his hands.
When Olive is being escorted from backstage to perform, the girl with the headset on has a clipboard when she approaches Olive, but when she is walking Olive down the corridor, the clipboard disappears and reappears as they get near the performance stage.
Frank's silverware order keeps changing in the diner scene with the ice cream conversation. At first the knife is in the middle, and then later the spoon is in the middle. After a few more cut shots of him the order goes back to its original one.
When they are in the hotel, and you see Dwayne and Frank open the door and enter the main event after being outside on the pier, you see a girl in yellow dancing. A few moments later you see a different girl finishing up with the same song playing.
In the part where Richard is explaining to the gang how he sold his idea to Stan Grossman, Frank is being sarcastic. When those two are going back and forth, you can see through the front window that the van is on the access road instead of the highway. You can see the stop sign approaching which wouldn't be on the highway.
The shots inside (when driving) the van all appear to be on rolling, multi-lane freeways in a heavily urbanized area. However, the exterior shots are quite varied, and as often as not look to be on two lane black - top, in a desert area.
In the hotel scene Dwayne is lying on the right hand side of the bed, after he turns the TV off, The Shot turns to the mirror where you see Dwayne now on the left hand side of the bed. Upon cutting away from the mirror Dwayne is now back on the right hand side.
When Frank and Dwayne are talking on the pier, Dwayne's microphone wire is visible through his shirt on the left side. Then at the end of the scene, the transmitter is visible under his shirt, also on the left side, under his belt.
It is obvious that most of the movie was shot in Arizona. The family lives in Albuquerque yet a shot of the van driving right after they start out to California shows saguaro cactus, which only lives in southern Arizona, and not anywhere in New Mexico (too cold and high). Even if they did drive south to Las Cruces and foolishly drive 400 miles out of their way and take I-10 instead of I-40 to L.A., there is no way they would be close to the range of saguaro so quickly after starting out.
There is a shot of the van driving and a green interstate sign that says I-40 to Los Angeles and then to the right of it 89A South and 89A North Exit Only. It also shows I-17 south to Phoenix. This sign is in Flagstaff Arizona, yet a previous shot showed the van next to an I-10 sign. If you get off on 89A you go towards Glen Canyon Dam. The trees on both sides of the road are ponderosa pines which do not grow anywhere along I-10 in Arizona or California.
Many shots of the van "driving to LA" show the van actually driving on I-17, the freeway between Phoenix and Flagstaff. If they were starting in Albuqurque there is no reason for them to drive on I-17.
A sign in the movie says "Scottsdale 23 Miles." Since Scottsdale is part of the metropolitan area of Phoenix and a suburb surrounded by other suburbs, there are no signs outside the city that would mention mileage to Scottsdale. All signs outside of the Phoenix metro area (or inside for that matter) would say "Phoenix 23 miles."
While watching the landscape through the windows of the van, the outside landscape often changes from the blasted flat rocky desert north of Phoenix on I-17 to somewhere in the LA suburbs on I-10. You can tell because one shot will have empty rocky desert and the next will have tall skinny Italian Cypress trees (which are everywhere in Southern California) and different looking mountains.
The van is supposedly driving from Albuquerque to LA (on either I-10 or I-40), yet in one scene it is clearly on I-17 just north of Phoenix near Anthem. The type of desert and small mountains and the vast amount of tan subdivisions in the background give it away.
The distinctive logo on the menus suggests that the family is eating breakfast at Pann's, a famous coffee shop within ten miles of the beauty pageant in Redondo Beach - yet somehow, it takes the family eight hours to get there. In actual fact, the restaurant scenes were shot with borrowed Pann's menus in Dinah's, a restaurant located across the road from where the pageant scenes were shot in the Culver City Radisson.
The freeway turnoffs, hotel and pier at the final destination are not in Redondo Beach. The location used for Redondo Beach is actually the Crowne Plaza Hotel near the 101 freeway in the city of Ventura, California.
At one point, the van travels south on I-17 and passes the exit for Carefree Highway (AZ-74), some thirty miles north of Phoenix. A short time later, the van is shown passing through Flagstaff, over 140 miles north of Phoenix.
When the family is "driving towards LA" there is a shot of them driving under a maze of tan freeway overpasses. It is obvious that this is an Arizona freeway (all the nicely landscaped tan rocks with perfectly placed desert bushes gives it away). In fact, this section of freeway with the overpasses is actually US 60 eastbound just east of Phoenix in Mesa Arziona near the Superstition Mountains.
The goof items below may give away important plot points.
After Dwayne learns he is colorblind and runs down the hill, with the family watching, the horn does not honk anymore. Usually the horn is directly connected to the auto battery, and would honk, even if the engine isn't running. The horn will continue after this scene.
Frank tells Dwayne that he cannot become a jet pilot because he is color-blind. In fact, it is possible for someone to become a pilot even with color blindness, provided that the color blindness is not too severe (demonstrated by passing one of several tests approved by the FAA).
As the Hoovers are driving away from the hospital after
stealing Grandpa's body, a piece of the sheet he's wrapped in is visibly caught in the rear door of their VW bus. The next time we see the bus from the back, nothing's there.
As they leave the pageant, we see them put two pieces of luggage into the back of the van, which contains only a sheet. The next shot, from the inside of the van, shows at least three dark bags in the trunk.
After 'kidnapping' Grandpa from the hospital, the van drives under a large freeway intersection with several flyovers. Moments later, the van can clearly be seen driving back under the same intersection in the opposite direction.
During the color-blind test sequence, a busy freeway with many trees can be seen through the window of the car. When the car suddenly stops (unlikely on a freeway) and Dwayne bolts from the car, the landscape is devoid of trees and slopes downhill. When Dwayne and others return to the parked car, it is now on a quiet empty street.