Continuity mistake: In the scene where Thunderbolt and Lightfoot are in the car with the crazy driver. The car goes over the embankment and as it flips you can see a wheel break off. A short time later they both drive off in the same car, with the wheel attached again.
Continuity mistake: When the girl is yelling rape at the motel, she is wearing a bra and panties. After getting some money for a cab, she puts on her dress and she is bra-less.
Revealing mistake: When Clint Eastwood and Jeff Bridges are being chased by George Kennedy and his partner, Bridges is driving off the dirt road down and embankment and you can clearly see that in the passenger seat is a faceless dummy instead of Eastwood or another stunt man.
Visible crew/equipment: At the very end, when Thunderbolt snaps the celebratory cigar in half, in the next shot as the Cadillac pulls away, the reflection of crew is visible on the rear of the car.
Visible crew/equipment: After Lightfoot steals the Trans Am, when he first encounters Thunderbolt on the run, he swerves into the field, and in a shot from inside the car, a piece of filming equipment on the hood of the car is visible through the windshield. Then Lightfoot hits Dunlop with the car. (00:07:50)
Answer: Since the crate was labelled machine parts, I'm guessing fraudulently.