Very interesting as to McCain. Perhaps someone can weigh in on whether or not a person on official USA government duty anywhere in the world can claim ‘ home’ rights during that time and for the place of service.
What matters is the parents. They can be on official US government business or they can be tourists. If the parents are Americans, so is the brat, and from birth, making him Natural Born.
Of course, the kid's NBC status comes from being a citizen by reason of birth, as opposed to immigration / naturalization. That has the inconvenient side effect of also including Zero, should he not be shown to have been born abroad to unqualified parents (not going to happen, Abercrombie notwithstanding).
Of course, some of the nuttier birthers are on the same side as Janet Napolitano when it comes to the military. They'd like to exclude from the highest office military brats born abroad.
The Supreme Court would have to determine his Natural Born Citizen status. Citizen parents in service to their country— military, diplomat, etc. would be the only exceptions, IMO.
I would err on the side of caution until they require potential Presidential candidates to pass a stringent security clearance test.
Born on American soil to citizen parents.