The Emperor is the monarch of the region that falls under the legal jurisdiction of Fairyland PD.
In Muppets Tonight episode 203, the Emperor approaches beat officers Clifford and Bobo, and asks them what they think of his new wardrobe. The cops immediately notice that he is naked, pointing out that they can see his "cute little doublet" and begin to cite him for indecent exposure.
They're about to arrest the Emperor when their chief arrives on the scene and lets him go. It's just as well since the Emperor left his tutu in the dryer and he doesn't want to let it shrink.