Stories of assembly line sabotage are as old as the UAW. In all of my years I have seen only one personally and it was a non-union built brand new Toyota. Many years ago a woman called in and franticly stated her Corolla accelerated out of control (this was years before drive by wire systems) She managed to get it stopped by shifting to neutral and shutting the ignition off. She was only a few miles from the dealership so I grabbed a manager and drove to her. When I arrived she was looking at the car like it just tried to murder her and her young son...which it had. She said the traffic signal at the busy intersection changed so she accelerated quickly through when the pedal stayed on the floor. This was a mechanical cable operated accelerator on a brand new car. I didn't really believe her but she was definitely scared. I opened the hood and was surprised to see the throttle was jammed wide open. It took a lot of effort to break it free and close the throttle. I personally drove it back to the shop without incident because she would not go near the car. Found a small plastic cover for the wiper arm pivot nut jammed in the cruise control actuator, the actuator is covered by a plastic shroud so nothing can fall inside which means it had to be placed there before the cover was installed. Both of the wiper pivots on this car had their covers so this was an extra part jammed inside the housing for the cruise actuator throttle cable. The woman traded out of the car that day.
This is not hearsay I was directly involved.