Originally Posted by
JungleBus
Because they're not actually assigned HK priority until they check in without a seat assignment. You start seeing them popping up on the airport standby list when people start checking in online. They're still figured into Av/Au(Cap) stats from the time they buy their ticket, though.
Within 24 hours of departure, I have found the Au number to be a remarkably accurate predicter (sp?) of how many seats will be open after HKs are assigned seats. The number of available seats listed on the airport stby list is useless until about 60-90 minutes prior.