I'm guessing that motherboard manufacturers may decide to do something clever in the bios, possibly with a non chipset based clock generator for the extras. Alternatively intel may decide to only implement this on the gx1-px5 (or whatever) board.
It will suck if they do. But if they do they'll lose buyers. (Us ) So I think they'll try to find a way around. And from what I've heard the i7's were supposed to be limited as well, but they're not.