This may be a stupid question, but .... Why would the airlines care as long as the miles are being used? I understand that the major airlines have some concern about the billions (trillions??) of miles waiting out there in all the FF accounts (of course DL now takes them when you die). I might think that the airlines would want the backlog of miles to be reduced. The only thing I can think of is that the airlines don't want kettles getting free trips with the money going to the broker and the seller of the miles rather than them; however, the miles were acquired by buying tickets (or using CC).