Since a large fraction of the miners are inside China and all of the hard currency exchanges are outside, this will cause a pretty serious fork. No doubt people will start trying to evade the block, but the GFoC works pretty well, and any evasion will take a while to start being effective. It'd also be easy to tell who was trying to evade (look for outside transactions in the chains they publish) and send someone around to chat with them.

Even if the two sides are eventually reunited, then what? You have two separate chains, with overlapping sets of transactions, which would make any sort of ad-hoc hack to splice one chain onto the other impossibly hard, even if the anarchists in the Bitcoin world could agree to it. The bitcoin voting algorithm would eventuall make one chain win and the other one disappear. If some of the disappeared transactions were yours, how would this affect your opinion on Bitcoins?