price may or may not be bullshit based on dealer and area. certainly not outside the realm of possibility. regardless though, dealer prices are insane for work like brakes.
you can buy bmw brake pads, rotors, and the sensor online for cheap and pretty much any mechanic could do the job without special tools and for much less.
HERES the real question... DID the car need both done now? the odds of both being as bad as the dealer made it out are low. also how come the CBS countdown didnt indicate this. there is also a sensor that wears down that will trigger a light.
our cars are pretty advanced and so is the system they use to read our key when we drop the car off. if she sat down with the SA while dropping off the car, and he read the key, he should have known that the cars computer was calling for new brakes before she even left the dealership.
i would ask to see the records from when she dropped it off, what info was on the key about the CBS status and what the car was asking for.
i would also look at the paper work and see if they actually quoted any thicknesses for the remaining material on the pads and rotors. the sensor wears down at a certain point (its is clipped in the pad) and if the car didnt show the sensor how was the pad actually that worn down. then i would be on the phone with BMWNA asking how a pad can wear down to the thickness quoted on the paperwork without the sensor going off. Then arrange to meet with the the BMWNA rep for your area.
If they did this to you, they have done it to others, he can look at records and find a trend and go after their ass.
Remind your SA that you cannot give them all 5's if you aren't satisfied.
When i get pissed at my dealer, i walk in with a red folder full of car records, ask them to print out my cars history, i make sure i have BMWNA written on the folder real big with a sharpie and the phone number underneath. It gets their attention.