It would and it has. In Mastodon-speak, this is called an "extinction event", and I have seen a few of those. Mastodon, however, has already implemented take-ou

It would and it has. In Mastodon-speak, this is called an "extinction event", and I have seen a few of those. Mastodon, however, has already implemented take-out feature where you can download all of your data at any time, including your friend list. How about backing up accounts in other servers? These could be encrypted with a key which only the user controls. Or perhaps the backup could be done encrypted in cloud storage like S3 (this would involve a paid account, obviously) so the user's presence could be resurrected in a different server? It might also be dandy to have "failover" agreements, where one server can agree ahead of time to failover users for another server, in case of failure.