I don't think that employees are allowed to enter surveys even if they have backup documentation. I may be totally wrong on this. I have often requested customers to give us positive reviews and have been successful. Getting 14 in a single day is far beyond my success rate.To me it looks like they saw that their first four reviews were one star, and wanted to find a way to cancel them out. They took these from comment cards or solicited surveys from their service department, and the dealership employees went and entered them in Cars.com. But it seems pretty clear that something is not totally "transparent" there.
Looking at reviews, in general, I noticed that if you google the phrase "All of the staff were very friendly and professional" it seems that this seems to apply most frequently to hotel and medical businesses. "not the typical pushy car salesman" seems to come up in a lot of reviews.