[never]

thanks for letting me know this. this actually explains a little detail in my hubby's case: he argued with the check-in agent, and at first, the agent said she was going to rebook without charge, she checked the availability and found no seat. Then, things started to deteriorate at that time. by the end of the day, they claimed no seat, need to buy a new ticket.

If I had known this 2 hour rule, I might have argued with them. but since they were so authoritative, we had to give up. but then, I realized there was something wrong in the sense that why it was us to be the cut-off point in the check-in line? if no seat and bad luck, we were flexible and ready to accept rebook. but they changed such an offer after finding out all later flights of the same day were overbooked (no seat).

If this 2 hour rule applies to Delta, then, our experience just shows a perfect example of how this airline does not care about its customers by completely ignoring this rule and using the information asymmetry to cheat us, and making us to believe that it was our mistake to be the cut-off passenger.