No, Apple has explicitly stated that hair style, glasses, hats, etc have no impact on the face detection.

so does it mean that to unlock the phone I just have to knock you out and put some sunglasses on you?

How would that be any different than knocking someone out and using their finger for the Touch ID?

Well for one thing it'd be a hell of a lot more work to cut off a guy's head vs. just his thumbs (if you want to unlock again later).

exactly the same, which means FaceID is not that much more secure unless as part of the authentication process you have to smile on cue or something

Apple has said it will work with glasses and hats

But not sunglasses.