>Given a whiteboard and one hour,

We, hiring folks, aren't limited to just that anymore. There's github, linkedin, hn/reddit posts, random google stalking, etc.

I can find a lot about you, your attitudes, opinions, ability to communicate, style, etc. that, or you for whatever reason (paranoid, on the lam, aren't passionate) have zero online presence).

The face to face interview is mostly to confirm or refute what I've already learned about you.