Agreed this is much more likely to be wide angle lens distortion than actual negative camber.
It is something that creative photographers can use to benefit certain effects , but not for trying to capture the a solid dimensional subject.
I suspect that most dealers nowadays just use a mobile phone for photos of cars for sale , and they have very wide angle lenses. I used to take photos for my nearest dealer of each car for sale and try to do it with a fitting background that showed off the colours to advantage and i used a collection of lenses depending upon what I was trying to capture. Now they don't do that any more.
PS To display one posh frock was being bold , to use two equally OTT garments was definitely tending towards exhibitionism .
