That flight dispatched with 1 open seat in FC and a number of Medallions in Y

UG failure on GA. But as I stated the flight left late. So most likely the GA was pressed to dispatch the flight.

And we are not suppose to upgrade someone once the door closes.
There is no way for us to know who was next on the list. The manifest doesn't show that.

I'm not going to UG someone because there are too many variables.
UG the PM on a L or UG the GM on a Y? We don't have that info.

We start doing random UGs and those on the higher fares that are in back when the FO on a L got that last seat.. God the complaining would be worse

GA Fail. OP Fail for boarding too soon. FA fail for being rude.