[wongarsu]

I was under the impression that internally Amazon can track whose item you got because every item gets a tracking sticker when it enters the warehouse (or even sooner, if the seller labels them to save money). It would be a bit of an UI problem, but Amazon could take your review and just attribute it to whichever seller provided the item you received, instead of whichever you bought from.

Of course that's of limited help because you can't reliably order from a specific seller, but it would help Amazon fix the problem, e.g. by giving them an easy justification to reject to do Fullfillment by Amazon for sellers with low ratings.