When I had a high end BMW the dealer did that on a couple of occasions.
The most I've gotten out of them is a one way shuttle, which is only available until about noon each day.
I had a lower-end BMW model from a dealer that also sold other luxury brands (and Honda).
Whenever I needed a loaner from the service department, I got a Honda. When I had the car in for service and the service rep could see I had more than 100,000 miles on the car, I still got a Honda. When I sold the car I bought...a Toyota.
A perfect sales opportunity completely lost.