Re: We might need a system to revoke citizenship permanently.
We have a system in place for removing citizenship. If someone wants to lose citizenship, just post up an ostrakon thread for yourself and we'll kick you out. (I'm kind of half joking but half serious too) If said citizen ever wants back in they'll have to go through the same application process as other non citizens.
I am more concerned about the loophole of renouncing your citizenship and going off the radar for bad behavior. Iskar, you're reading too much into the wording there. Displaying means someone who isn't showing the badge, not someone who has resigned.