What year do you think we're in exactly?
Every year MB comes out with a new body style for one of their cars (classes). So every year there are suckers out there that do it, just have to wait one more year and the same body style car they can get for MSRP or lower . This doesn't happen with any other German car that I know of, its weird, but it happens. This also happens with Ferrari's, Lambo's and many other super cars or one off "special" releases.
When I see a C class or a CLA going for 10k above retail, its like WTF!