Case in point if Marshalls gets a large number of returns for Widget X because of a defect, how can you be sure it came from the most recent shipment of widget x or a shipment that sate in a warehoue or store for 2 years? You cannot with any certainty - without your own manufacturing identification system.
Storage conditions are also important, but again once it has left the factory or distributor that is out of your control, no matter who purchases it. Granted, 3rd party items are more likely to have been stored incorrectly, but that is not exclusive.
As to returns, Amazon deals with returns all the time. If as a seller you fulfill from thier centers (IE any Prime sale), they will take the return. If a customer returns to the manufacturer instead of the store (marshalls, amazon, wherever), it is because they are making a warranty claim, and well you need to be equipped to handle that regardless of the source of the sale.
But I am responding to an AC.
I work hard to ensure that my sources are not counterfeit, but since I primarily purchase retail, I have no wholesale distributor invoice to prove authenticity. While not abused yet, there are situations where a manufacturer or other seller will claim a seller has counterfeit items to remove that competition. With the brand registry, I see this as happening more, and small sellers will get hammered by what are essentialy NOT good faith take down notices. This can result in complete removal of a seller account, shutting down small and legitimate businesses. There are many sellers that DO abuse the system and sell counterfeit goods, but this system will not discriminate, and many of those will find other ways to skirt the rules.
Google is currently using Deepmind's AI to control its server rooms, where it manages windows, fan speeds, air conditioning, and more than a hundred other factors to save Google hundreds of millions of dollars in electricity costs.
So they are able to save money where they control all parameters. Fine.
How are they going to manage windows, fan speeds, air conditioning, and more than a hundred other factors in normal houses?
With a nest thermostat?
The president enjoys authority over classified information, of course, but at a minimum it would be highly irregular to disclose an intelligence wiretap via Twitter.
And what about the cheeto POTUS is not highly irregular?
New York... when civilization falls apart, remember, we were way ahead of you. - David Letterman