"For targeted - it often doesn't because often your AWS keys are on the system doing the back up and have permissions to delete items etc."

Just a reminder - snapshots at rsync.net are immutable.[1]

Even if Mallory gains access to all of your access credentials, she cannot delete/change the snapshots in your rsync.net account.

[1] https://twitter.com/rsyncnet/status/1453044746213990405