Okay, let me say up front, I am not a lawyer. But I find this interesting. As far as I can ascertain, two articles in the Outerspace treaty render it rather silly.
Outer space, including the moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means.
So, If I move to the moon, I am not, at that point, a citizen of the US/Russia/China/UN whatever. Or at least I am living in not place that any Earth based government has any legal right to regulate. This includes any country that signed said treaty.
Article VINow, from article II we know that no government has any jurisdictional power over any "celestial body" and therefore none over any person on that celestial body. So no government has the ability to assure any actions of a person on said body.
States Parties to the Treaty shall bear international responsibility for national activities in outer space, including the moon and other celestial bodies, whether such activities are carried on by governmental agencies or by non-governmental entities, and for assuring that national activities are carried out in conformity with the provisions set forth in the present Treaty. The activities of non-governmental entities in outer space, including the moon and other celestial bodies, shall require authorization and continuing supervision by the appropriate State Party to the Treaty. When activities are carried on in outer space, including the moon and other celestial bodies, by an international organization, responsibility for compliance with this Treaty shall be borne both by the international organization and by the States Parties to the Treaty participating in such organization.
Basically what I am saying is that any group of people who go to the Moon, for instance, are immediately exempt from this treaty because no government on Earth has the legal right to enforce the treaty on the Moon.
So a group of citizens can go to the Moon, and assemble all the WMDs they want, and there isn't a damn thing the US, UN, or any other country who cares can do about it (except withdraw from the treaty and attack the moon).
So, am I full of it? Or have I found a loophole?
Update 9:38pm: I forgot to mention I got the text of the treaty from http://spacebombardment.blogspot.com/