Perhaps this will turn out to be just the sort of tool the Bitcoin community needs to keep mining pools from gaining too much market share? Or perhaps it will usher in a new stage of mining wars. Either way, it seems like it has the potential to alter the balance of power by giving the mining community some power to punish misbehaving pools.
If a situation arises where it's no longer safe to accept hashing power from random members, then pools would have to restrict themselves to only working with trusted participants. Presumably that would make pools a lot smaller, and there'd be more of them.