As I mentioned on the other similar thread, dealers will ALWAYS try it on. For some reason it just seems to be a universal law. In my 20 years of car owning experience I've not met one who hasn't yet. I got stung once many years when I was young and naive but never again and the fact that they use the "safety" argument to get you to agree to work which 8 times out of 10 doesn't even need doing is quite frankly disgraceful and should be outlawed.
Just do what I do, tell them to change the oil, stamp the book and give you your car back. Any other work that "needs doing" you can take to a reputable indie. I use a guy who was an ex BMW master technician and a German marque specialist who has been doing it for years. I remember a few years ago when my wife's CLK was in for a service and the Mercedes dealer tried to tell me that all the discs and brakes needing changing and would cost £600, I took the car to the indie who told me the brakes were fine and wouldn't need doing for another 7-8000 miles. This happens more often than you'd think.