If someone were to wander into a hospital (or police station) today with complete amnesia -- no idea who he was or what his life had been like -- and that person could not be identified, no family or friends could be located, etc., what would happen to him?
What governmental agencies would become involved, and what would they do? Would they assume he was a U.S. citizen? Would they give him a social security number? Would they simply kick him out onto the street to fend for himself?