Do these things also get released if the person holding them dies? (the reasonable assumption being that only a tiny fraction people will bother or care to act

Do these things also get released if the person holding them dies? (the reasonable assumption being that only a tiny fraction people will bother or care to actually make arrangements for this) Or even without death, the idea being urbit "property" is all cryptographically locked tight, correct? So can a planet get lost? If someone loses all their keys or a server park gets droned and the dog ate their backups or something?