I was travelling yesterday with my husband (who does not fly much), and I was to meet him at the airport. As usual in this day and age, our 3:45 CO flight EWR-ORD was listed as delayed till 4:45pm. I got to the airport about 2:45, checked in and proceeded to wait and wait for my 'better half'. He shows up at 4:10pm, and we proceed to the PC. They tell him the flight (while still not in yet) is restricted to gate check in. We go to the gate where to my husbands surprise and great dismay, he is told "sorry, but when you didn't show up 20 minutes before the original stated flight time (x-delay), we gave your 8D seat away, and now the flight is completely oversold, so we have no room for you at all on that flight! , and can only put you on standby for the later one!!!
His complaints that the flight was delayed, and thats why he arrived late, fell on 'deaf ears'. Luckily, there was a EWR-MDW leaving at the next gate in 30 min that we were able to get on, and with my CO Platinum elite status get FC with a companion upgrade . So in the end it all worked out--but it could have turned out very differently.