It's not a matter of it being "activated" per se. They just need to swipe your credit card and driver's license once. After they do that, on subsequent rentals you just get in your car and drive off. For this first one you *may* have to stop at the counter/kiosk, but yes you would either get on the Avis Preferred line or go to the Avis Preferred kiosk in the garage. You don't have to stand on the "regular" line if that's what you're worried about.