I truly think the reason this goes on is the gradual dumbing down of America (quoting a national talk show host" I think the general public does not want to look stupid so they just go along with things, especially if they don't understand them. Most people won't question the extra charges because they don't want to come off as being stupid. The dealerships and businesses in general has keyed on this, and it is now SOP. Those of us here on MercedesShop tend to be more independent and think "outside of our box".
I recently attended a job fair with a major telecommunications company and one of the questions on the entry form was "are you bilingual?" I circled "yes". I was introduced to the national manager and another person. We went into a room and the third person started to speak to me in Spanish. I politely explained that I did not speak Spanish but was fluent in German and Japanese. The national manager asked why I had indicated that I was bilingual. I found myself explaining to her what bilingual meant (trilingual was beyond her comprehension) . This is a person with an MBA, a six figure salary and VP status. No wonder dealerships try to take us for suckers.