I work at a dealership and we can decline service to whomever. We do it to some customers who are basically a "pain in the ass" and complain all the time about everything so its less on us. Granted we might get a bad survey from them but its better than multiple ones because we have some that are just never satisfied. Not only that but if they are understaffed and don't have someone who can take a whole day looking at the car they can decline too unfortunately.