Originally Posted by
ft101
If you receive a gate upgrade then checking in on-line will not have have a difference as the decision to upgrade you will have been made after check in.
However, if the flight is being managed prior to check in, including allocating op-ups, then checking in on-line shows that you more than likely intend to fly. You may be op-upped at this point in preference to someone of equal status who hasn't checked in.
Even if they don't make a decision to op-up until one hour before (after everyone is checked in), is an earlier check-in time used as a tie-breaker after other critieria like status, fare class (flex/saver), . . . ? That would seem logical, although most experiences here seem to think that it's just arbitrary.