Originally Posted by
WineCountryUA
While agreeing on the likely reason, there is a process for donating miles which the airlines view in a similiar manner. Although RPUs/GPUs would be a more complicated process with the expiration issue, restricted geographic usage and the need for an underlying paid ticket.
It's a good point, but I would respond that upgrade instruments are different from miles, which really have become a transferable currency. Not only can you convert credit card points to miles, you can pay UA to transfer them between accounts.
Also agree on the additional complicating factors.