I haven't followed all the technical details but there was some pretty strong words about how the anti-fork brigade had a plan to attack the forked blockchain and it *seemed* reasonably scary what they were saying. Maybe it was overblown? Maybe some of those folks have come around now?
Nope. But not to worry; if a fork actually happens, they will have no wherewithal to attack the new chain.
If miners like the idea, they publish the new block version number in their headers. If they don't, they don't, and no fork happens.
If 75% of the blocks mined in the last 1000 have the new block version number, the miners are free to make a >1Mb block. But nobody has to. It could be quite some time before an actual >1Mb block and subsequent fork happens. Anyway if a fork does happen at that point, the people who want to "attack" the block chain have, by procedure, less than 25% of the hashing power. Which flatly isn't enough to have a noticeable effect on the new block chain.
If and when we reach the point where 95% of the blocks published in the last 1000 have the new block version number, then clients will start rejecting any blocks with the old block version number, and the fork will be enforced from that point onward whether the blocks formed are >1Mbyte or not. And if the fork happens at that point, the "attackers" are left with 5% or less of the hashing power, and the threat of an attack is sort of like pointing an unloaded BB gun at an elephant.
