I remember reading a story about this years ago… probably urban legend, and my details will be off, but it goes like this:

A toothpaste factory had a QA issue where some boxes would leaves without a toothpaste tube inside. To rectify this, they hired a consulting company to the tune of millions of dollars who designed and built an elaborate scale under the conveyor belt that would sound an alarm when an empty box went past. An employee would be stationed there to react to the alarm, find and remove the empty box.

This worked swimmingly, until one day the owner realized he hadn’t heard the alarm going off in quite some time, so he went to investigate the problem. He found that the employee who was stationed there was annoyed by the alarm, and had set up a floor fan blowing across the conveyor belt prior to the scale - blowing off the empty boxes before they were weighed and triggering the alarm. His solution had cost $10.