Limits

• The framework tracks a landmark by its id text. It is not known whether two landmarks in the game can share one id.
• If the map screen will not show a marker, the entry is still kept, and the call can still look successful. Unlock reads the loaded map back, so it gives back true. (AddLandMark still keeps the entry and gives back false in that case.)
• Unlock does not check that the landmark belongs to the map that is loaded. Whether the marker then shows on the wrong map is not known.
• A saved landmark is only put back if the game’s map load succeeds for that map. A map the save never wrote has none, so nothing is restored there until the next save. (The restore needs OnLoadingGame to give back true for the map’s controller.)
• Reading the map’s data directly can still show your landmarks. (SaveData.Capture on the map controller, called by a mod outside a game save, still sees the mod landmarks.)