Peter Spiro notes that "appeals from courts in the cities would be to Mauritius and then to the UK Privy Council... This strikes me as the leading edge of a potentially huge development, in which private actors more formally get their own pieces of turf and the lines between sovereign entities further blur. ... it will require legal innovation to situate the new, private city-state in the world of international law."
I still think this is just a new twist on an old idea. But I agree that there are serious implications for thinking about the nation state, sovereignty, autonomy, and the rule of law.