"More details" - well, it seemed to me that the mess and question boxes are displayed to all players on the map. Suddenly, one clicks OK, and the other clicks CANCEL...
Added 7 minutes later
In the game, through the single-player menu, there is a checkbox that opens multiplayer maps in the map menu. You can "lock" it, but even then, various tweaks or tools that modify the configuration files will change things where they shouldn't.
