In a really egregious example, I bought a set of OEM TPMS sensors that were re-packaged with the full intent of defrauding the buyer. They had the nut installed (real OEM new ones do not) and there was an even film of dirt (black; likely rubber dust) on the sticky potting material on the backside of each sensor. Topping it off they were sealed in plastic bags that made an attempt at looking like official OEM packaging.
Another example, ordered a blower motor resistor ($$$$ for the GMT800's with the digital controls) for the '06 SS, it came as just the module in the box, nothing else - especially the harness (necessary), and the adhesive foam gasket already applied to it. It was a lifetime warranty part from Advance so I'm pretty sure it was someone's bad/returned part.
Neither of those were an "honest mistake"
Richard