The Nordschleife is basically a public (toll) road open to anyone (and I mean anyone - I've seen tourist busses and cars towing caravans) at specific times, so it is not legally required to wear a helmet (in a car). Some do, some don't.
The face is blurred probably because they banned cams a few years back after too many people got killed "driving for the camera." If they catch you, you get blacklisted. That goes for the driver, not the car (which in this case should be easy to ID).