On the Knights of Noromath server, Baronies & lesser holdings benefit from various systems and methods of control placed in the hands of players.
A Baron can create a Bailiff Writ.
A Baron can access the doors of their barony and make changes anywhere in their barony.
A Bailiff is able to access the doors of their holding and make changes at that holding only.
A Bailiff can create insignias of their Barony.
A Bailiff or Baron can create a key to that door.
A Bailiff or Baron can change the DC on locks/break DC.
A Bailiff or Baron can declare if a room is public or private.
A Bailiff or Baron can set the rent for a room.
A castle door that is locked demands a certain amount of upkeep in gold pieces. The higher the difficulty on the lock DC and break DC, the more costly a single door will be. Bashed doors cost a barony considerably, as well.
Several feats modify this system, including Leadership (reduces overall soldier/knight upkeep), Landlord (reduces overall holding upkeep), Siege Engineering (bonus to taking down doors), and Masonry (bonus to fortifying doors)