About ten years ago I worked for a defense contractor that did
performance-based contracts. (The gov't says "we need a product than
can keep a dozen eggs fresh for a week," and you invent and provide the
product.)

One of the contracts we filled was to replace the electronic rodent
control devices with something else - something that worked. I was
assigned to "install" the new product - house cats! This was a large
military facility, so plenty of fields and such for the cats to go poo
and nobody around to be bothered by them, so it ended up working out
well.

When I arrived to install the product, the guy in charge said the
electronic devices not only didn't work, they gave some of his guys
headaches. (You could actually hear them.)