Quote from Eiviyn: Go
Correct me if I'm wrong, but publishing a map as "Locked" just removes the triggers. Obviously, melee maps don't have triggers.
According to the Galaxy Editor, when you select to publish your map as locked it warns you that no one including yourself will be able to open the locked map after it is published. The warning recommends you save your locked map as a new file and make updates on a local, working copy.