The only airline that is still reasonably ethical regarding upgrades is AA.

US Airways is actually practicing consumer fraud. They say they have "unlimited" first class upgrades for their Chairman's Preferred flyers at 7 days prior to flight. But, they are capacity controlled, and now it is their policy to withold whatever seats have not sold, up to the number 9 until day of departure (and usually, time of departure so that they can sell the upgrades. What this means is that at 7 days prior to flight, if 10 first class seats are unsold, only 1 will be given to a single Chairman's flyer.

It is very important that US Airways go our of business because of the 34 ways in which they have disconnected completely from their customers, including their top 2% of frequent flyers.