They seem to imply that the seller was actually honest and thought it was genuine, so I guess somebody did get shafted in the process (although probably by a much smaller amount).

It's quite a clever hustle in a way: since the wrapped box is worth so much more than an opened one it's an interesting paradox: if you don't open the box, you don't know for sure that it's genuine but if you do open it then it loses most of its value. Therefore if you manage to make a convincing fake using a clean box and some shrink wrap-fu it will probably be hard to ascertain the authenticity of the product without damaging it.

It's like Schrodinger's Pikachu.