Continuity mistake: Just before Nick talks to Tracy for the first time, he is drinking a beer. Between shots the level of beer noticeably lowers. (00:26:15)
Continuity mistake: When Blaine and Duane wreck the airport radar, Blaine throws a hook at the radar and it lands in the slot fourth from the right. In the next shot the hook is now in the slot third from the right. (00:29:50)
Continuity mistake: When Randy asks the officer "how fast was I going," his seatbelt jumps from under to over his collar between shots. Again, when Kimberley is begging him to stop at the Barbie museum, the seatbelt repeatedly jumps from over to under his collar. (00:37:00 - 00:39:50)
Revealing mistake: After Duane falls from the hot air balloon into the oasis, you can see the shadow of the hot air balloon basket, but the shadow of the balloon itself is missing. (01:02:45)
Continuity mistake: While Duane and Blaine see the two girls in another car, the one with a lot of piercings has her right arm down inside the car in one shot, but in the next shot her arm is on the car door. (01:21:55)
Visible crew/equipment: When the gang run toward the Silver City Station, they reach the door, struggle a little (as they're all fighting over getting inside) and then they enter. As they arrive at the door and then struggle, from the shot inside you can clearly see the reflection of the camera in the glass of the door. (01:29:10)
Revealing mistake: When Seth Green is taking money out of the Donation Jar to put in Gambling Machines, he is not getting any money out and pretending to put coins in.
Revealing mistake: When Blaine is getting Duane to put the money in the bag, you can see at one point he tries to stop himself from laughing. This is because on the special features of the DVD there is a 6 minute long outtake where they both keep laughing on this take.
Revealing mistake: After Mr. Kameechi throws up on the airplane as part of a bet, he puts the "throw up" bag down on his tray. If you look closely, you will see that the bag has absolutely nothing in it (it's flat).
Continuity mistake: In the scene where Duane and his brother are trying to delay all the airline flights, a few seconds after his truck goes through the fence, you see a shot with everything in it. The rope in this shot is curved, when it should be straight, as the radar is pulling the truck. (00:31:45)
Continuity mistake: When Cuba Gooding Jr.'s character is being chased by the Lucy look-a-likes his jacket is sweaty and dirty. Then when he wakes up in front of the horse pasture it's perfectly clean and bright white, like it just got washed and bleached. (01:23:00 - 01:23:55)
Factual error: After the helicopter crash lands, the girl tries to re-start it. The sound is from a piston powered helicopter. The helicopter in the movie was turbine powered. (00:48:10)
Continuity mistake: When Rowan Atkinson and Wayne Knight are in the van, there is a car in the lane beside them. When they switch lanes, this car which should be behind them is gone. (00:58:50)
Visible crew/equipment: When Vera and Merrill go zooming past the car repair man's garage and the garage collapses, as the man turns and mutters "whoa," the camera's shadow is clearly cast on his back (01:16:00)
Deliberate mistake: There is a clear shot change as the monster truck lands on Blaine & Duane's Cadillac. One minute they have JUST fallen out of the car and fell to the ground, and the next they are at least five feet away and running, full-speed.
Continuity mistake: At the end when the highrollers are aboard the private jet, the outside shows a small plane, but the interior shot shows a huge plane with tonnes of overhead room.
Continuity mistake: When Tracey and Nick are at the gas station, the clouds in the background keep changing from shot to shot.
Visible crew/equipment: The shadow of the camera truck is visible in the cow pasture.
Other mistake: When Seth Green falls into a desert oasis, he causes a huge splash, but in the next closeup there's only a few ripples around him. (01:05:25)
Continuity mistake: When Duane and Blaine burst into the monster truck rally, a hub-cap comes off one of the front wheels. But, for the rest of the scene, both hub-caps are still in place.
Answer: They only had blanks - the non-cut keys that are used to make keys. So when they saw those, they knew that the guy had their key.