It seems as if they're already doing this by playing with the number of seats allocated to EUA, etc. For example, say there are two platinum elites on H fares and one on an X fare at the five day window. EUA allocates two seats and viola the high fare two get upgraded. They continue to play this game every night based on the number of high fare tickets purchased. In this way they can upgrade the folks who have paid the higher fares and allocate anything left over at the last minute to those of us who still have money in our pockets. I've not seen any notification of this, and I wouldn't expect to see any. I have some empirical and a lot of anecdotal evidence of this.