So you believe if King George had fathered a child with an American woman, the founders would have accepted that child as qualified for the presidency?
Respectfully, in the scenario you mention, does it matter if he did it in the U.S.?
I know it is crazy to think of George III touring the states, but it was almost as likely as him taking a run at an American ex-pat at the time, and actually claiming the child.
My point is that plenty of communist, and even islamic terrorist sympathizers are born here every day. Our sovereignty is not particularly in jeopardy if an American citizen procreates here or elsewhere. The NBC stipulation is vague. One must decide intent by precedent and writings of the day, not what-ifs.
Just my opinion, and as I said, it is submitted respectfully.