Revealing mistake: When RoboCop goes to arrest Dick Jones and starts to shut down, as he twists and turns we can see his real left arm in a black body suit under the costume.
Continuity mistake: When the ED-209 kills the businessman, his chest and tummy are covered in blood. However, when he falls backwards, the shirt is clean except for a small spot with blood.
Visible crew/equipment: Robocop shows up at city hall and is hounded by reporters. We see his point of view. The shadow on the bottom left is that of the camera filming the shot. It noticeably has a shade so light doesn't reflect into the lens and is visible at least twice.
Continuity mistake: Murphy has blood on his head right after he's shot in the arm. It wasn't there before.
Continuity mistake: During the beginning shootout, the police car's windshield is shot twice, obscuring visibility. The cop car pulls up along side the van. The holes in the windshield are gone. They return in the next shot.
Visible crew/equipment: Before he collides with Lewis, when the camera goes in close to Clarence driving you can see the camera crew and equipment reflected on the door.
Continuity mistake: In the steel mill, as Clarence and company are walking along, in the wide shot Murphy comes in from his left side holding a piece of metal. In the close up he picks up the metal to toss.
Continuity mistake: When RoboCop is in the chair for the first time, he is recording Roosevelt saying ahhh. When RoboCop is ordered to play it back, Roosevelt says ahhhh but the tone is much higher.
Revealing mistake: When Robocop uses his thermal vision to see the hostages and gunman through the wall, you can see a long zipper in the back of all the thermal color pattern costumes they all wore to simulate thermography. This was most likely invisible to the eye in a dark theater but on an HD screen, it shows.
Continuity mistake: During the pursuit of the armoured van when the gang open fires on the police car, the amount of damage to the car keeps changing throughout the scene.
Visible crew/equipment: As Robocop first drives out into the city, there is somebody's head in the extreme right side of the frame, even though he's alone in the car.
Continuity mistake: While Clarence is interrogating Murphy, Emil is holding his shotgun by his side. In the next shot, he is holding it across his stomach with both hands. (00:21:25)
Revealing mistake: As Boddicker swings the bar at Murphy, as Murphy's head drops down while deflecting the bar, the skin make-up at the line where it meets the part covering the back of his head wrinkles up a moment.
Continuity mistake: When ED-209 is firing rockets at Robocop, the launcher pops up, and the first rocket launches. A moment later, the launcher pops up again, but the top tube has a rocket. The second tube launches, the top tube is empty. Obviously a re-use of the original shot.
Visible crew/equipment: As Robocop walks through the abandoned house, his memories of what it used to look like come into play. The gold vases in his memory reflect the camera crew and equipment.
Continuity mistake: At the convenience store, Robocop stops the burglar from fleeing by knocking him on the jaw, making him fall backwards. A frame later Robocop's arm is extended and the man is flying forward, falling face first.
Visible crew/equipment: Right after Clarence Boddiker blows off Murphy's hand with a shotgun, Murphy turns around grasping his wrist and begins to face the four criminals that are about to kill him. During this scene of him turning around, you can see a crew members fingers move in the bottom right corner of the frame. We know it's not Boddiker's fingers, as he was just wearing black gloves when he shot off Murphy's hand. (00:22:35)
Continuity mistake: When the ED-209 shots and kills the guy in the suit, his body changes angle and position with respect to the robot.
Continuity mistake: Robocop is being hounded by reporters through his view point at the City Hall. When the camera switches back, he is away from them, near a car.
Revealing mistake: When Bob gets killed by the main bad guy, his pants have unusual bulges in them, the blood packs.
Answer: Because he knew he was doing illegal activities. Robocop was said to be highly efficient at his job and Jones did not want to risk him out on the streets without the insurance of shutting him down if Robo came after him.
MasterOfAll