Hmm, I'd never thought about the possibilities of that sort of thing. For example, you could set up a "I haven't been able to login for at least 24 hours" text to go out, and just push the date forward every day. I might have to look into one-click ways to do that sort of thing, so somebody can notice if something happens to me... :)

"If you're reading this then it means the exchange went badly and Johnny John Johnson killed me. The proof is in a safe deposit box etc etc..."