@Data10 makes some good points. I think that Stanford, more than anywhere else that I know of, seems to look for applicants who are out to “change the world” in some way, more than just academic achievers. I think it’s pretty predictable that the combination of athletic excellence and social outreach demonstrated by the young women discussed in the OP would be highly appealing to Stanford, and would far outweigh standardized test scores so long as there was other evidence that she was able to handle to academic rigor.
@bluewater2015, another way of looking at it is that even if Stanford rejects 69% of applicants with a 2400 SAT, that means they accept 31% of them, which is over 5 times higher than the general acceptance rate of 5.3%.