Re: Factory worker's note found under front carpet
When I worked at Wixom Assembly in the 90's, it was pretty common that the floor pan wouldn't be clean before the carpet was installed. Not usually with hand written notes, but various wrappers or tape.
Other things that were common were substitution of fasteners by the line workers. One guy's job was to install the fuel filler neck, secure the carpet, and I think secure one other item. Each of which required a different screw. He used fuel filler neck screws to secure everything.