... I have read that if the Power/Wake button is pushed 5 time in succession that a passcode becomes mandatory to unlock the phone....
FaceID requires only 2 failed attempts to require the Passcode.
Federighi addressed some mitigations, based upon an inquiry from developer Keith Krimbel (see MacRumors), regarding a thief taking an iPhone X and pointing it at the owner. Federighi replied that if one has been gripping (he did use the word "grip") the buttons on both sides of the X, prior to it leaving the hand, this temporarily disables FaceID.
Another question to Federighi was about wearing sunglasses. He responded that as long as the sunglasses allow enough IR light that FaceID can see the eyes (even when the glass becomes opaque), FaceID will accurately recognize the owner. He was not implying all sunglasses will be Ok; just most.
Here's a link to MacRumor's
How FaceID Biometrics Work ...So, there are nuances about FaceID that will soon be better understood by the wider public. While unfortunately, the general, news media is not seeking accurate details from either Apple or reputable, tech reporters who were at the  presentation (like, iMore & David Poque and got accurate updates) before reporting, and as result, the media is inaccurately commenting on the FaceID based upon fallacious bias and egregious questions.
