Note that due to refactoring, the fix-autojoin admin action is now slower than before, but I'd say this doesn't matter, as this is only used extraordinarily.
I see some potential for refactoring. It is not necessary to get instances from the database for each individual user. But as you said, speed is not really important in this context.
Note that due to refactoring, the fix-autojoin admin action is now slower than before, but I'd say this doesn't matter, as this is only used extraordinarily.