Boundary fence can be built only within a village claim. It can be used there instead of personal claim when it's needed somewhere else. Or it can be placed on a personal claim to give additional protection there.
Player who finishes first cornerspot becomes owner of all fence parts and gates which are built from it later. When gates are built a key is generated. Those who have copies of it can enter freely.
A player can turn criminal acts on and pick a lock, this would take some time and leave a theft scent at the end. He can try to destroy a part of the fence, and this would be an act of vandalism.
Optionally, lockpicks could be introduced. They could hasten breaking into the fence, or even reduce scent units left near the gate based on their quality.
As for materials, advanced metals (bronze/iron/steel) could be used to build this type of fence. Or large amounts of stone...
The purpose of boundary fence is to restrict access to some areas, mostly without using a claim. Players can use them to protect private house and land around it, or to restrict access to important warehouses of a village.