You can't wave away that the intent is a large part of the rule. It's a simple matter of if they seceded to circumvent the ability to only recruit in the capital or not. An instance of that would be CE or Darka allowing dukes to secede so their army could respond to attacks on the perimeter more easily. Happening to gain an advantage in the process of sensible IC developments is not prohibited. An advantage which I still attest is negligible considering the state of the realm, even recognizing other characters join.
