The pan lid flies into Ernest's face in the restaurant with its handle towards him. When he pulls it off, the handle is facing away from him.
When the shop vac goes up the walls and on the ceiling, huge creases are in the walls and ceiling to keep the vacuum in contact with what it is rolling up against.
When Charlotte and Ernest are in the restaurant and the spoon flies up and sticks to Ernest's shirt, the wire is visible on the spoon as he puts it back down on the table.
When Ernest becomes magnetic and locks himself inside the vault, the drawer about to get attracted to Ernest has a number showing "175." But when the drawer is trying to bust open, the number says, "183."
During the demonstration of the invisible, bulletproof, plastic wall, Bobby fires 14 shots from a six-shot revolver.
Right after the waiter gives the menus to Ernest and Charlotte, the camera angle changes and you can see him walking away, and hear him saying "I'll give you a minute to look over your menus" as if he was still standing there.
At the bank, when Chuck picks up his boombox to change the radio station, he turns the knob all the way on the left. His boombox is a Sanyo M9811, and on this model, the knob all the way on the left is for the "tone" setting. For this model, Chuck would have had to turn the larger knob on the right to change the station.
When Nash throws the chair at Ernest, you can hear Nash say, "Here, have a seat!", but his mouth clearly does not move.
Even a crooked attorney would know better than to secretly arrange a switch between a criminal and an innocent man.