Last week I abandoned a flight ATL-TPA when it became three hours late. I also booked a backup flight myself while I waited. It also started to show delays (past a midnight departure). So I left. Tried to stop at the ticket counter as I left the airport to cancel. Jammed. Called while driving home to cancel both trips. When they called back at 1AM, they told me both had been automatically cancelled and already refunded. So they are still being lenient.