Visible crew/equipment: When Dr. Faxx is programming the new directives into RoboCop, the camera pans around RoboCop's body. You can see the reflections of a camera and a crew member on RoboCop's helmet. (00:47:55)
Visible crew/equipment: When Robocop visits Cain's hideout and sends his car in as a decoy, after he returns to the car, watch the driving shot closely. A wire has magically strung itself across the entrance and attached itself to the back of the car - it wasn't visible from an earlier shot. As the car drives forward it stretches the horizontal wire, and just as a tiny amount of pressure is exerted, the car explodes. Yeah, it's technically a mistake, but I think it's more worth checking out just to see how those tricky effects are achieved.
Visible crew/equipment: Watch very carefully when RoboCop shoots the man in the yellow shirt in the factory scene. The man falls down the stairs and just as he reaches the bottom, a pair of hands come out from the bottom of the screen to break his fall. (01:00:02)
Visible crew/equipment: When Cain and his gang are making their escape from the drug factory at the start, we can see a crew members hand very obviously poking out from behind the door frame, giving the actors their prompts when to go.
Visible crew/equipment: At the start of the film, RoboCop is in his police car, and it gets hit with a rocket and it flips over, and then slides to a stop. It is quite obvious that RoboCop is not in the front of the car, and that a silver plate has been placed in the driver's seat to make it look like he is.
Visible crew/equipment: As Robocop is stood up after electrocuting himself, the crew and equipment is reflected on his front.
Answer: Just so it would look creepy in the jar (or maybe they thought they were worth keeping, then decided against it). Notice when Robocop pulls Kane's brain out of the 'bot later, the eyes are no longer there.
Grumpy Scot