"Well, in practice, I'm the only one who can actually stop you from doing whatever the hell you like with Fairyland, and if I thought I might have to do that I wouldn't be trying to hand it to you in the first place. A Vicereine or Viceroy is supposed to do what the Emperor tells them, but the ways in which this is enforceable against mortals mostly don't hold up against you even without all of Fairyland in your pocket. We would pretty much be trusting you to just politely refrain from spending the at most two hours it would take you to find out your own Emperor's name despite our best efforts to hide it, and in return for your forbearance and general cooperativeness with imperial directives, you could fold yourself into our galactic reputation for being a really bad idea to try to conquer, and have the assistance of our military in protecting yourself and the Queen against external threats."