I'm not sure what Amazon does (looks like they don't actually track) but from the consumer side you basically get a random item. Say you order a specific product, like a Macbook charger, Amazon sends you one from any number of vendors and you most likely get a counterfeit one and you have no idea who the product came from. Look at the reviews for a product like this you can often see a bimodal distribution of people who got a legit item and people who got junk.