Just checked- and Doc. 4444 section on applicability over the high seas has been removed (amended 1996- good to see I stay up to date????). Now the only applicable refs are Annexe 2, and article 12. So basically ICAO claims contracting states do have authority over the high seas. Which leaves you with the chestnut of States claiming the high seas. Impossible to win (warning-lawyerfest).. .As an aside: The biggest abuser of this rule (Annexe 2) would have to be the US mil, even though the US is a contracting State! "....bearing the markings or registration of a contracting State...." pretty clear imho.