Originally Posted by cova
It is not that EUA is not run, it is that R bucket gets changed to 0 just before the EUA time. I tracked some recent flights DCA-IAH-DEN-IAH-DCA. The DEN-IAH was held back after normal 5 day EUA and released about 3 days out - even though only 2 out of 18 seats were sold. R was available during the day - for mileage upgrade - then R was not available late in the evening before EUA.
That's interesting. I wonder if CO has been doing this (releasing R seats and withdrawing them before EUA runs in the hopes of mileage upgrades) for awhile or if this is a more recent strategy.