Sure...If the flight is posted as "on time" and the clock gets to 30 min, then it is taken to "gate control" and seats of unchecked people are released. Now let's say it goes on delay, and the plane now leaves 1 hour later...those seats are already gone and cannot be "gotten back" (unless they have not been reassigned yet.)

A flaw (or maybe not a lfaw as it MAY be by design...) in this system, is that even if the flight is at gate controll, and other CSR's in the lobby annot process you, I have seen ez-checkin machines over-ride that gate controll and check people in based on the new dept time. This HAS caused problems for me, when at 25 min prior, I clear all upgrades and standby passengers, effectively filling the plane for an ontime dptr. The plane has a mechanical, and those that now arrive (late) for the original dptr time in the lobby, and use the ez checking machine, adds them to my "need a seat list". There are no more seats....the passengers missed the cutoff, their seats were reassigned in accordance with UA policy. Now they come to the gate asking for their seat, and I have to explain that their reservation became invalid due to failure to check in on time. It makes for an ugly scene.

Most of the time this doesn't happen, but I have seen it happen on numerous occasions (we can check the checkin history to see when the checkin was proceesed and by who (or what if a machine.)


As for can we tell if you a connecting customer, and not drop your seat? Sure, if you are checked in for our flight already. If you are not, we must assume you didn't show for original flight, were rerouted...etc. It is nearly impossible to look at inbound flights that have connecting passengers booked, but not checked in, pullup each and every passengers record, and see if/how they were re-routed, and if they will be making it to our flight. The system as set up assumes that if for whatever reason, you are not checked in by 30 min prior to posted dptr time, that you will not show up.