Revealing mistake: You can see the charges to break the glass armor at the chest of the first guard when Violet kicks down in the vault. (00:16:30)
Revealing mistake: During the motorcycle chase, when Violet is on the building, the chopper gunner badly damages the exterior of the building, with brick and glass particles flying all over the place. But these particles disappear without a trace when they've moved a few feet away from the camera.
Revealing mistake: During the fight with the men in white suits, all of these men use swords. Violet disarms a few of them, using then to cut or stab them with. But every time she slices, or better, tries to slice, you can see that the swords never actually cut, but are used as a sort of baseball bat. Also, they are sharp enough to cut someone, because Violet's hands are all cut open at the end of this fight scene. It simply means that these swords are blunt props, and that nobody did anything to make it appear that they are real.
Chosen answer: Simple sex-appeal, no plot significance.