A typical WiFi internet connection is located at the dealership, paid monthly for limited bandwidth access, limited control, private or public access. The dealership has limited knowledge who's logged on/off and for how long, this could be costing the dealership even more money monthly.
A social WiFi hotspot is a WiFi bridge that allows public users access to the internet. Mobile user give permission, sign on with a social media account in exchange for sharing dealership promotions or marketing pages. The dealership marketing department controls the mobile experience, such as length of user time on line, and types of car or truck promotions users purchase, helping the dealership turn the WiFi service into a profitable mobile marketing machine.
Interesting use of a captive portal, but it's a stretch to call it "mobile".
Your four line title is almost longer than your advertisement.