Another thing since nonrev's can print the seat request card 24hrs before departure, so you could see a lot of NR's verified and make you think there are too many ahead of you (AirportStbyList) and you won't get a chance if it's a full load. Then these individuals don't show up. I've had that happen to me before and still got a seat on a tight flt. It use to be that if you saw them on the list you knew they were "in" the terminal. A little more accurate accounting on the stby list.