public virtual void ExcludeMapFromSaveUnit(
	Type MapType
)

If you want to save most maps, but not all, you can call IncludeInSaveUnit(SaveUnitInclusion) to include all maps, and then call this to exclude a few. Maps not included in the save unit (and maps that were not loaded when the game was saved, even if they are "included") will be reset next time they become active after loading that SaveUnit. Often times an overly map does not contain any important state information, so excluding an overlay map from a SaveUnit might be a good use of this function. See IncludeInSaveUnit(SaveUnitInclusion) for more information about save units.