Originally Posted by
NWA012
From the reasoning I was told this would make sense for either not to do this, but to answer your questoin this is for gate agents. "Once a customer is settled with belongings in an overhead bin they are not to be moved." I could not believe what I was hearing! This may not be the true policy and may be more of a local thing that has evolved at my station. Again, I follow the PMNW policy of going on board when time permits and upgrading before the door is closed.
The "official" Delta policy the last couple of years has been that once the boarding pass is scanned and the passenger has boarded on his coach reservation, the upgrade comes off the table for that passenger. There have been numerous conscientious gate agents who have come on board to later upgrade a coach passenger who went ahead and boarded, but my understanding is that this is not required. There was even one thread on here a year or so ago from a Delta employee implying that this activity was discouraged, although clearly not forbidden.
This is why, when one is on the upgrade list, the question to ask the gate agent is not "Has first class checked in full?" but instead is "Has first class boarded full?" If the answer to the latter is no, then you should remain in the gate area in order to preserve eligibility for the upgrade in the event of checked-in no-shows.