williamcorke - the car in the fake ad was the 5th series currently for sale in NY.
The B20 on Bring a Trailer that you reference was also a legit advert from a few years ago, that was a 4th series, which went to a broker in California and was in Germany the last time it was offered for sale, perhaps last year.......
Both in similar trim, both RHD.......
Meanwhile however, these things still do turn up - legitimately. Attached is a real Craigslist advert from two weeks ago, it was only active for a few hours....
The Subito ad has now been removed, but the photo that they were using (the one I saw anyway) was from the BaT feature, with the BMC race transporter in the background.
I posted that Craigslist ad on this forum while it was still live, little suspecting what a BIG STORY it actually was. If I'd only looked at the photos with more of an eye for detail (shame!), I would have noticed the mountings for factory/PF bucket seats, a clue that this was no ordinary B20. As I expect quite a few of you on the forum now know, this car was 'flipped' to Switzerland for a very impressive amount of money (approx 25 times the asking price from the long-term owner, if I've been correctly informed).
So yes, they do still turn up...