The returns thing doesn't fly. No one in amazon is taking sealed shipping boxes and putting a new label on them, assuming that the item is inside.
No, but if you have the facility to apply new shrink wrap so it looks factory sealed, Amazon aren’t going to x-ray it to check what’s inside.
Hm, that's an interesting fraud vector. Presumably it applies to pretty much any retailer though? And doesn't apply to items with tamper-proof factory seals that are hard to counterfeit.
You only have to counterfeit it to the standard of Amazon's returned-items check though, not to the OEM's standard.