A) The SCOTUS definition of NBC is self-limiting. "These are the natives, or natural-born citizens, as distinguished from aliens or foreigners." IOW, if you are not born in the country to citizen parents, you are considered a natural alien whose claim to U.S. citizenship is in doubt and must be resolved by either constitutional or statutory means.
B) In U.S. v Wong Kim Ark, the court ruled that to be satisfy the subject clause, the parents must have permanent residence and domicil.
If there's such a thing as an "anchor baby," it is the result of a misapplication of statutory law and has nothing to do with natural-born citizenship.
The law is that if you are born in the United States, you are a natural born citizen.