Let's put this to bed. Returns and refurbs alike are binned into lots of, say, 50 units. Third party repair companies bid on them. The winner takes possession, runs triage according to apple protocols and apple diagnostic tools, performs any needed repairs out of pocket, and then places them up for sale linking in to Apple's web store. The products may also be sold in-store.
Any purchase of a refurb is fulfilled from the repair shop with generic packaging. Warranties are reset to day 0. The end.
Oh, and scuzzy remanufacturing shops will sell the truly fucked unrepairable gear in-store and try to pass it off as new. Get caught and Apple will annihilate you.
My guess is that it's primarily the likelihood of failure soon after purchase which is greatly decreased.