I'd imagine a few. They shouldn't have to amit it or say what dealer their from (wouldn't want to have to field complaints on a forum ya know). It's good for the actually because #1 They'll see what "hardcore" owners are complaining about. #2 Access to upcoming changes in the mode line (remember BMW sales people only want to tell the customers what 'is' not what "may be").
Also, just as there may be BMW salespeople on the site, their competitors will also be on the site (maybe).