proof of life is just a timestamp
classic dead-man's switches refresh a lastActive field on any transaction. a bot on a cron, a delegated signer, or an attacker holding your stolen key can all keep that clock alive forever while you are not.
a Selfie Check, not a signature
checking in requires a fresh World ID liveness and uniqueness proof scoped to your estate. a private key cannot look into a camera. whoever holds your key cannot pretend you are still here.