Re: Nothing to hide
"hard-to-get-to place behind the windscreen (in addition to the one on the car ID plate) "
1: It's not hard to get at if you remove the windscreen and even without breaking the screen there's somewhat of a dark industry in making fake vin plates that can be slipped into position without looking out of place. I'm a bit surprised that most makers haven't put some kind of tamper shield around the location.
2: The VIN is stamped on a half dozen other (usually undocumented) places on every european/japanese/american vehicle made in the last 30 years (it was one of those hidden VINs which identified the truck that Timothy McVeigh used). This is how "cloned cars" are usually confirmed, as crims are only going to change the 2 obvious locations and expect that the mark won't check the others.