This must be a BMW thing. [although I've heard similar complaints about other high-end dealers]
They should offer another option: for an extra $100, the dealer WON'T wash, polish, or even touch the paint prior to delivery.
We got our Mini Cooper through the local BMW dealer and somehow we lucked out that they did not have time to take the buffer with the dry steel wool pad to the car before we picked it up.
VERY nice recovery. The owner should present the before & afters along with a bill for your services to the dealer. They won't do anything of course, but it would let them know that people are geting wise to this and that they should pay attention.