Originally Posted by
lucky9876coins
Technically not, but I hear of them opening up seats for GS's all the time when they request them. Both for awards and upgrades.
I don't know about "all the time" but certainly "from time to time".
For example: 1 for 2 on getting C-F transpac upgrades confirmed in advance* (got the second one day of departure). Opened another XF for Mrs. CTW on an award IAD-ZRH this summer when only one saver was available.
But definitely not "anytime, anywhere". The Saver F was the only available date with Saver between July 1 and August 31 when I called back in February for that route.
-C
*That is, opened up NF and then confirmed starting from NF0.