There is a reasonable fix for this though, just set a reorg limit say 100 blocks, and prompt for manual intervention from the user. Given a prolonged network partition situation, there would be either a central or democratic procedure to determine the winning branch, via a checkpoint. This assumes that network partition does not happen too often for longer than a day in practice.
Actually this might be the approach ppcoin eventually adopts.
that means that anyone who can create 100 blocks can shut the network down 'forever' if that'll never happen, why secure against it? If you have some consensus method that can easily resolve the shutdown why not use that for your consensus system instead of a PoX hashchain? ::meh:: It might actually be a prudent sort of thing to do, but I'm skeptical.