You've kind of broken to core concepts of the game. One, you either are a noble or you're not. A noble cannot lose their nobility. Nobility is due to your birth. You can't lose your birth. This may not be historically accurate, but it is the way we handle it in the game.
Second, we do not want nobles to want to be rogue. Nobles belong in realms. We do not want to add any positive incentive for nobles to desire to be rogue.
