In this case you don't need to divine his intent because the strategic advantage is self-evident. If I'm playing soccer and the ball touches my hand before entering the opposing goal, then the goal doesn't count. By having a cooling off period, you nullify the advantage and maybe even create a disadvantage for the seceding and parent realms, which is ok because it's self-imposed. If they don't like it, they can wait until the war is over to secede.
