Originally Posted by RobOnLI

Then you are clearly not reading all of the material that UA & CO are sending to you and you're not reading FlyerTalk. It's been discussed, ad nauseum, about using the correct FF# for your flights. There are specific, well documented and generally accepted reasons why CO & UA have implemented upgrades the way they have. Regardless of where you book the ticket, whose flight code you booked, etc. you should always use the FF# of the carrier *operating* the flight.