I don't think it'd benefit HN at all at this time, as the country of origin just isnt relevant most of the time, and would just invite flamewars. I believe that flagging/downvoting is a good enough tool to deal with stuff, as the HN mod team puts in the work.

Maybe once the site gets 10x as big and the mod team gets overwhelmed, it could serve a purpose, but I doubt that to ever be the case.