How about...
... and ...
When the password box is not checked, the entry fields for the password will be faded out, but dull. The password is to prevent others from editing your map, and should be saved inside the map file itself, possible encrypted. This can prevent others from embedding your tilesets, stealing ideas, background, quads, envelopes, etc.
Map author should, obviously, be unchangeable unless you can reach the password. In fact, the whole properties page should be hidden unless you can reach the password.
Important: If this is used, make sure that the map name in the server browser is read from the internal name, and not the name of the actual map file. For example, the map above, named "The.Teeworld01" should be shown as "The.Teeworld01" in the game browser, regardless of the fact that the actual filename is "world.map". This can also prevent others from renaming your maps as their own. An example of this is: I rename dm1 to "dm_super_by_nuby" and many noobs will think that it is by me... whereas it is not.
Thanks for reading. I hope you replay with feedback, and tell me what you think. Should it be implemented?