Bandit's glory time ... We use hours of hours and resources to build fortifications whether it is palisades or stone walls so it only requires one to two bark boxes to jump over the wall. solution to this problem could be to make an invisible wall from the top of the wall and up so that the only possible way to get across the wall must be through a seige ramp or by destroying the wall. however, it should be possible to jump out from inside.
Or give us the opportunity to hire NPC to protect our claim by reacting as soon as someone who is marked as an enemy / bandit or if a member is attacked inside the claim area.