This goes back to around 1990s. I was an independent designer for a few different printing businesses in the South suburbs of Chicago. Back then computers were fairly new and print shops were still old school. Those inserts you found in newspapers? They were still hand lettered back then!!! I’d design brochures and flyers, laser-print proofs, scan photos (a 150 dpi HP scanner was $1200 – that’s like $5K today!) and so on. Anyway, one of the print shops had a customer that ALWAYS found an error, would demand a new proof, and not authorize the job until he signed off on the new proof. Every. Single. Time. “This line is crooked” “This word is too dark” and so on. So we came up with a solution. I’d do two proofs. One was the original, accurate one. The other has an obvious intentional mistake. He’d catch the “mistake” and ask for a new proof. He’d be told to come back in an hour (it was usually a day or two.) He’d come back and be shown the 2nd proof. He approved it every time. Demand that there’s always a mistake? Here you go!