Revealing mistake: At the end whenever we see a shot of the large crowd from the stage point of view look closely.You can see how the image of the crowd has been tiled because people are transparent. They must have filmed a small section of the crowd then duplicated it to make it appear that there are thousands of people there.
Factual error: When the brothers are both in the pond and one of them comes up covered in pond weeds, notice a few places on his body, for instance the side of his head, he has a plant attached to him called Water Hyacinth. This plant not only does not grow in the South West, but also floats and you can see that there are none floating anywhere on the pond, especially in the middle where he landed.
Factual error: During the monster truck scene, the brothers line up their car with others that are to be crushed. All of the cars have their windows and antennae intact. In a real crush, they would all be removed for safety purposes, ie. No flying glass and pierced tires.
Factual error: You can see Joshua Trees many times during the movie (During the Rocket Car scenes, for example.) There are no Joshua Trees outside the Mojave Desert.
Visible crew/equipment: When Duane is hanging on the rope, going through the cow pasture, when he hits the second cow you can see a person's hand in the bottom left corner of the screen. (01:04:00)
Continuity mistake: When Randy and the family enter the hotel room, they put the bags down and go round to the boudoir area. In the next shot the position of the bags by the door has changed. (00:10:05)
Visible crew/equipment: The safety wire attached to Blaine's right side is visible when he notices the rope around the radar tightening, and gasps / flinches. (00:30:10)
Continuity mistake: When Jon Lovitz's character wipes Eva Braun's lipstick off him and onto the steering wheel, it appears to be dark red. But after the crash and the formation of the "Hitler mustache", it is black.
Continuity mistake: When Seth Green and his brother are chasing the keymaker, they fly over two embankments. In both shots, upon impact they break the A-pillar in the car, resulting in the nose of the car pointing upwards and the area directly under the windscreen bent down, common in a stunt like that. In the next shot of them racing along the paddock, the car is perfectly normal.
Deliberate mistake: In the infamous coin toss scene, Cuba's call is disputed. However, it appears that the coin on the ground is in fact in agreement with his call. However, he explains later that they use a special commemorative coin that is hard to read as it may have what appears to be a head on both sides. Therefore, the coin may have had a head come up, but it was agreed that that side would be 'tails'.
Continuity mistake: At the "Feed the Earth" concert, as the lead singer sings "It's a cool place, and they say it gets colder..." watch the guitarist - a microphone on a stand appears in front of him between shots. (01:39:40)
Continuity mistake: In the scene where everybody is racing downstairs, as they all fall in the corner you can see Vera is wearing high heels. Later on in the film, especially noticeable at the rocket car scene, she now has flat shoes on. What, did they take a trip to the shoe shop during their frantic race to Silver City? (00:22:00 - 01:14:25)
Continuity mistake: At the monster truck ralley, in the first shot as the monster truck revs up, ready to jump the ramp, look at the huge advert signs behind it. One of them has "PowerBar" written on it, but in the second shot as the truck roars over the ramp, the same sign is now totally different. (01:23:25)
Continuity mistake: You can see the pierced girl that Blaine likes standing behind him on the "Feed the Earth" stage before we actually get to the scene of her climbing onstage. (01:35:25)
Continuity mistake: When the car repair man cries "Oh Lord, I'm here. And I'm listenin'" the oil rag he holds in his hand changes from being dark red to a much lighter red between shots. (01:15:50)
Continuity mistake: When Kimberley says she need to go to the bathroom, the family drive past a restaurants' sign, but in the next shot if you look through the back window, the sign has vanished. (00:35:00)
Continuity mistake: When Duane is about to give Blaine his key, he realises it's a fake and he then lifts the other key up, and this on has a chain on it (I think it's the tracker device, which means they still have the key that the key-cutter stole), but in the next closeup the chain has gone from the key. (00:52:20)
Revealing mistake: When Owen tells the Lucys that he stole the uniform and that he isn't a bus driver, one of the Lucys asks, "You're not a real bus driver?" By the end of the sentence the old Lucy is lip-syncing the question. (01:20:00)
Visible crew/equipment: In practically every scene throughout the movie the reflection of blue screens and reflectors are visibly reflected in Vera's glasses. (00:07:35)
Continuity mistake: At the start of the scene where the taxi driver leaves Owen out in the desert, in the first wide shot of them driving on the road, the road has no markings on it. In the next shot of inside the car, you can clearly see out the back window of the car that the road now has double yellows lines running across the middle of the road. (00:35:40)
Answer: They say, in turn: "Hello, Ladies!" "We saw you runnin' on the highway" "Without a chaperone" "Somebody has some s'plainin' to do".
ChiChi