They recommended IE6 too but the main issue wasn't what the user saw when visiting the page, it was the supplier CMS used to administrate it. This was enforced by Mercedes themselves, so all dealerships had to use it.
It was custom, and, this is no exaggeration, impossible to use. There was probably a 600 page manual, caked in dust in some forgotten supply cupboard, detailing what exactly you had to do after you'd managed the Herculean task of logging in.
Editing a simple block of text required 'unlocking' it, which would for some reason lock other elements. And then when you did change the text it might not have let you save it anyway, providing plenty of incomprehensible error messages.
I must have put a mental block on the rest because I quit after just a day of figuring it out, but my guess is that pages like that still exist because no bugger can figure out how to edit them.
I'd be surprised if VW didn't use the same or a similar CMS themselves.