How the scam works - Apple sends their junk to China to remanufacture/recycle. There instead of being ground into a fine dust some end up in chinese panties to be smuggled out of the facility. Next someone pulls out most profitable still working parts, puts the phone back together and tries to pass it thru warranty process again: https://appleinsider.com/articles/18/10/09/rampant-chinese-i... Apparently they managed to get a grip on Chinese fraud, so scammers moved operation into US.
There is no such thing as Genius at the "genius" bar, they arent allowed to repair anything (can only sent it up the chain to Texas afair) and often dont even know how to open products, not to mention being able to tell what should be inside.
It's why I have been able to harvest my old units for parts and cover a substantial cost of each upgrade. I even sold a completely broken iphone 7 mainboard for $40, without fingerprint reader. I literally found the phone smashed to pieces on the ground (with SIM removed).
They’re already “broken”. No need to overprotect anything.
As an Ebayer, most of my shipments are in crumpled re-used Amazon packaging with 50 stamps. At least I type out the “TO” address.
I can buy that the guy sending them back may not have known, though again the quantity he was sending should have raised a red flag. But the guy who was receiving the broken counterfeits and returning them to Apple? No way he didn't know he was doing something shady.