Penny wise and dollar foolish.! If a seat is empty, and someone with a paid ticket for a later flight is already at the airport, he/she should be allowed to board at no additional charge at the end of the boarding process, as always. In addition to having already paid, that customer is already inconvenienced with respect to time and uncertainty, and if he is not boarded and is a President's Club member, he will just consume more food and booze. Most important for CO however is the fact that if that customer leaves early, there will be a seat available for a later walk up who will have to pay the highest possible fare. Keep the standby off that flight and there will be no place for the walk up. I see no advantage to CO, but regard the fee as a removal of one of those features that have made CO the airline of first choice for many of us and that may end up losing more in sales than in gaining revenue.