The 'account' consists of the credentials required to add or modify data associated with a human.
In that case, the person deleting their private key would suffice for deleting an account.
There are plenty of things this doesn't cover, or even backfires. Just interested in what other perspectives people may have.
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Scuttlebutt actually could allow for 'deletion' in the sense that a 'compliant' scuttlebutt client could choose to interpret a 'delete this account' message as a filter for any messages that match said public key. Many client's UX understand that the state of messages may be incomplete due to the P2P nature, so thats kinda nice too.