Just a thought, but could you link the “Entering Lands Ruled By” message to a craft-able item? Like a clan banner? This would allow individual clans a choice to go loud & proud when carving out their own piece of the blood-soaked soil, while allowing survival-by-subtlety for others.
In addition to a clan banner with a reasonable cost, you could link the same behavior to some massive high-cost monument for those brash & brave clans who want to scream a challenge to the world! A little end-game resource sink for bragging rights…
While I’m spit-balling ideas, maybe make such a monument server-unique. So if your clan wants to build one, they’ll have to tear down the old one. All in the name of blood for the Blood God!