The returns fraud issue is a difficult one, and still very much an ongoing issue particularly with Amazon, as recently as yesterday when I ordered a used copy of a video game listed as returned to Amazon, and received an amazon warehouse sealed package containing a completely different game with the sticker replaced, so clearly not tested at all during the returns process to ensure it did actually work.
Now, as for a solution, is it too much to expect Amazon to test goods they then go on to sell again? I would previously have assumed they did this, but apparently not.
Luckily, the returns process is quite easy, which both leads to this issue in the first place but makes it easy to resolve.