A visual signal that indicates an incorrect quantity of parts is about to be shipped to customers, allowing the operator to correct the problem before it is detected by a customer is an example of what?
Based on the scenario being described within the question it can be said that this is an example of Poka-yoke. This is a Japanese term that means "mistake-proofing" and refers to any kind of mechanism which helps an operator avoid mistakes during a process. Such as eliminating defects or detecting incorrect quantities before shipping.
