If it's an occasional mistake, cut some slack (check history to see if he was doing cleanup) . If it wasn't, then it's process-for-the-process-sake-wonkery-wonkery-willy-wonka kinda guy and should be sent to room 101
I think this is an example of where process should be followed even when it seems pointless. If we don't follow it then the banning policy is actually "Banned users are not allowed to make useless edits.", rather than "Banned users are not allowed to edit." The former is not a useful policy (it basically makes bans a form of probation).
All edits by banned users should be deleted, if they're useful, they can be remade by someone else who can take responsibility for them.