Getting an account that can sell on the US will be a bit difficult but shouldn't be that big of a deal. Then again, Blizzard can always slip something in the EULA that can get you into trouble if you play a lot from an address different than the one in your battle.net account, claiming you listed and incorrect address and must prove it or something, and of course only use that part of the EULA on the Chinese farmers.
If they only sell gold, though, only the farm's manager really needs a US account to list a ton of gold on the RMAH (since each "stack" of gold which you list at once counts as 1 of the 10 listings, unlike items where each item is its own 1 of the 10 listings). That can be easily worked with and wouldn't break any rules of Blizzard, since after their announcements they can't prevent Chinese from playing on US and they can't prevent Chinese players from "giving away" gold to their "American friend" who then sells it on the RMAH in his own region, gets the money out to his bank account and pays the farmers their paychecks.
So IMO item farming will be reduced (but probably not at all eliminated) by it if Blizzard really wants it to, but gold farming will be almost as rampant as it would have been without the restriction.
What do you guys think about people in Asia resorting to third-party sites in order to carry out real-money transaction? Would they resort to that? Or just deal with not having a RMAH of their own until Blizzard figures something out?
Personally, I hope they perish in a fiery crash...and then something heavy lands on them. Sorry. I'd rather be taken advantage of by people who actually care about the game, like all of you for example.
guys, clue train: it is perfectly legitimate to farm gold, its perfectly legitimate to sell gold, it is perfectly legitimate to choose whichever market you want to participate in, even while being asian/chinese. ffs.