The problem is, that's an extremely niche situation to be in, while people wanting to be a lone wolf ninja are a dime a dozen. It invites abuse, and is not a generally helpful feature.
It's not something I'm going to say I would absolutely never ever do, but even if I approved it now (which I won't), it wouldn't be implemented and sent live in time for it to help you if you actually want to leave a realm right the hell now.