I think it is funny that the dealership would not want to do the work under warranty. I am reading several threads on this forum about warranty issues/denials. I would think that as long as the dealer could feel good about the issue not being total neglect that they would honor the warranty without question.
Coming from Fords for the last 10 years or so I never once had a warranty claim issue. I had a lowered modding GT500 that the front bushings were squeaking. Very easily they could have said "nope not going to fix this as it is a result of you lowering the car". Not only did they fix it without question, but they replaced the other 3 at each of the corners just to be safe. $800 fix no questions.
I would think if it is BMW HQ decision they would be way more flexible especially in times like these. My car is brand new and now I am a bit concerned and hope I never need warranty work. Seems like it will be a hassle.