A customary way that friends in Southern California leave events together: two or more people walk to one person's car, and that person drives everyone back to their cars.
The Southern California Goodbye is a response to lack of public transit in a region which is now literally over 14% parking lot (not counting freeways, which in Southern California are also effectively parking lots).
SoCal person A: Where did you park?
SoCal person B: This side of the parking lot. You?
SoCal person A: That side of the parking lot.
SoCal person B: That's hella far. Southern California Goodbye?
SoCal person A: Thanks fam.