You're right, the dead man's switch is interesting here. I wasn't thinking about the ability to reference a fairly precise point in the future via block number

You're right, the dead man's switch is interesting here. I wasn't thinking about the ability to reference a fairly precise point in the future via block number instead of an external input to the system. Don't get me wrong, I'm pretty excited about smart contracts. It just seems like there are a lot of things that we don't think much about currently because our current system is generally pretty forgiving in its fuzziness, but that could have big consequences (and introduce new incentives to act badly) in the world of script-controlled, irreversible contracts.