There’s probably some sort of esoteric loss-protection algorithm that feeds inscrutable variables about the product, the given user’s past behavior, the disposition of the entrails of the goat slaughtered each morning under the gaze of the data science group’s machine vision system, etc. into deciding whether or not to demand returns in a given case; just to keep people on their toes.
There’s probably a (comparatively) trivial cut-off below which the reverse logistics just plain isn’t worth the hassle, and it makes no sense in isolation to request a return; but the incentive to game the system if it becomes well known and predictable that Amazon just says “not worth the hassle, keep it with refund” in certain cases would likely become a problem.
What is more puzzling is why they don’t seem to be doing any classification(or at least not effective classification) of goods between “can plausibly be revalidated” and “the inspection it would need cannot be justified by potentially getting to sell it”: There are, presumably, some goods that can be given a fairly quick once-over and classified as either fine or not; but others where the risk of contamination (as with drugs or cosmetics) or the incentives to reasonably sophisticated fraud (as with high value computer components or jewelry) would absolutely require more inspection than you are going to get from random warehouse conscripts, and potentially so much inspection that it’s just not worth aiming to ever list them a new.
You certainly see a lot of that when PC OEMs are selling stuff on their own account: basically anything that was a corporate bulk order config, or where the box so much as left the warehouse, gets marked as a refurb and sold separately. This might cover for some ‘refurbs’ where the CPU and GPU have both been swapped for the cheapest lookalikes that will still boot, not sure how often people get burned in the ‘refurb’ department(I usually do fine but I also don’t buy a statistically significant number of units); but it keeps down the incidence of mysterious scratches, missing protective film, and tampered OS installs in the ‘new’ section considerably.
