What does, "Not for sale or charter to US residents while in US waters"mean when looking at boats?

I see this all the time when looking at baoting magazines.|||The most likely reason is that the vessel has not been formally imported into the US... it's still owned/based outside the US, so it can't be sold within the US until the import formalities are carried out. (And the taxes paid...:-)|||This means that it is a foreign built boat and is not documentable in the US by the currnt owner. They have not paid any duty on it. It is not built in the United States and is owned by a foreign owner. It is not documentable in the US because of the foreign manufacture, nor is it usable for charter.|||Probably tax or privacy issues the seller has.