Nan: But that is the problem. There has to be a priority.
Only the poster can edit the message body because he owns his post. He can also delete his own posts.
Admins can delete, and edit surnames, classification, and subject. So maybe once an admin edits those fields no one should be able to touch them except the admin and staff.
Staff edits or deletions should take priority over any others.
At least that is the way I THINK it should be or as you note it could be an endless battle. That is the main reason I think the editor should be noted.