So folks, what is the latest on using soon-to-expire RUC's on flights post-expiration as long as there is confirmable space today?

I swear I have done this before. I also swear it is a rather regular thing to do in these parts as long as the ticket gets reissued before RUC expiration.

I am trying to burn a few for Christmas travel on a flight with confirmable space. One HUCA got me upgraded...but the ticket was never reissued. A call last week got me downgraded when I asked to be reissued! Three more HUCA's since have simply read me the T&C's. Has anyone had any luck with this recently?