It's Prussian-controlled, and even provides the Prussian treasury with $2, but the area is neutral and out-of-bounds so Austria can't ever take it - hardly seems fair.
Besides, Emden was the scene of some rather swashbuckling action in the 7YW - real Douglas Fairbanks and Errol Flynn stuff. I have to at least be able to send the PCs there on a suicide mission!