I have not had this problem, but I have had other problems that BMW was either unable or unwilling to correct.
1. Window tint applied by the dealer interferes with AM radio receiption. This is very annoying as that is what I mostly listen to. After complaining for a year they finnally acknowleged the problem, but their only idea for a fix was to remove the tint in the rear window. How stupid would that look.
2. This was'nt really a problem with the car, but a problem with service. I had the tires replaced. Went to the dealer to have this done as I was very concearned not to have the rims damaged (I have the M style rims included wih the sport package). Well, they totally screwed up the rims, scraped them all around the outside edge. When I complained, their response was, "That is just to be expected when you change these low profile tires". I said bull! After a week of going up the chain, BMW of North America was no help, said this was a dealer issue. I said bull! The dealer has a big BMW sign in front and in my opinion they represent BMW. Anyway, after about 2 weeks of hassling they agreed to have the rims re-finished. If it were not a leased vehicle, this would not have been acceptable, but since it is just a lease which will be turned over in about a year I agreed.
I guess my point is, I love the car, I've never really had any problem with stuff original to the car, but I am really unhappy with how the service department takes care of problems. I have also owned an Acura, and even a Honda, and their attitude was great, treated me like gold every time I walked in the door. My BMW service manager is very nice, and I like him, but basically it seems if I have a problem, its like you said, if they can figure out how to fix it they treat it as if it is normal function and you are out of luck.
I love my car, but these things have really lowered the joy of owning a BMW. I think next time I am going to take a look at an Audi or Mercedes as a result. Too bad