Bet she's not have a hospital birth, instead a homebirth, but they have done this to throw the media off the scent.
I was 2 weeks over with S and 3 weeks over with O. And boy did I get sick of the constant phone calls, texts, fb messages etc. (and you vvers were probably sick if hearing me moan ) and I could not believe how many vague acquaintances wanted to know when I was in labour. What's up with that?
I would say she's enjoying some aircon somewhere very comfy.