I have seen this happen with a bad result. The person I know was checked in F on the web with no issues and when they got to the airport found themselves sitting in a bad seat in coach.

What most likely happens is when you have elites that did not get upgraded, someone from the airline manually goes through and looks to see if any seats have opened up and or they release seats still being held for revenue.

However by exposing the possible flaw in the system on this board you most certainly can guarantee that the loop hole will now be closed in the future...It might work but if you get caught it could cause you big problems and risk your status and account..

If you have not already got caught by flight time you will have problems when they use a diffrent system to do a match on the FF# and Passenger name for purposes of giving Mileage credit.