Amazon may be able to determine the source of stickerless comingled inventory like this, but stickerless comingled inventory is treated as interchangeable on the fulfillment side. So if I order an item "Sold by ACME, Fufilled by Amazon" I may receive a copy that was shipped in by "Cyberdyne".

Amazon's tracking will internally tell them I got an item that was sent in by Cyberdyne, but they don't tell me about that.

This as a customer means I can order an item from ACME, that I know is extremely careful about not selling counterfeits, but end up getting a counterfeit, because Cyberdyne is super sloppy, and the one I got actually came from Cyberdyne. Even though amazon can track this internally, as a customer I have no idea the one I got came from Cyberdyne instead of ACME.

For some products the counterfeits may look the same, and even function the same, but cut a lot of safety corners etc to be cheaper to make, and I might only know that I got a counterfeit after it catches on fire, and burns my house down, possibly losing family in the process.

At this point if I complain Amazon can look it up, and point the finger at Cyberdyne, but it is a bit too late by then.

If ACME instead went with the stickered non-comingled option, I will get one of the items that ACME actually sent in, even though they might need to send it from a further away warehouse, if the closer ones only have the comingled stuff.

Absolutely true - but it's the sales strategy that is 'co-mingled'.

I was just responding to OP's point that implied that this is a side-effect of how the inventory is physically stored, rather than a decision on sales strategy by Amazon.