Originally Posted by
cova
I interpret this to mean that the probably of getting volunteers on low fares to give up their seat is low. At very peak times like this - the flights are all full - so getting a volunteer is unlikely.
Hotel guarantees are the same way - guaranteed availability for top tier hotel elites, except there are a few high peak situations where the guarantee does not apply.
That's what I think. People would be IDB; I bet the system tries to figure out if there is a way to get them to their destination later--if it doesn't look good, it probably negates the guarantee.
As others have indicated, CO tends to play a little loose with the meaning of words such as "guarantee."