If your reservation is for Fastbreak then you go straight to the car. The paperwork is done at the exit booth from the car lot. Very fast. At LAX there are huge queues for regular rentals, it takes 30-60 minutes to pick up a car most of the time, with Fastbreak it is 1 minute, and the nicer cars seem to be put into the Fastbreak lot.

A few small Budget locations offer Fastbreak but in a pseudo-version: you have to do it at the rental counter; but I've only seen this in smaller cities, definitely not at LAX and I cannot imagine that SAN would be like that. Best to phone the 800 number to verify that you are reserved as Fastbreak and what the pickup procedure is at the renting location.