Originally Posted by jrblack
So clearly you would have cleared the WL on SEA-LAX, but the system wouldn't even let you request an UG! Geez!

Yup. Fortunately, the plane was empty so I had 8E open (as well as 8E open LAX-IAD which was very nice). And I obviously would have cleared at the SEA RCC/Gate if I had asked.
But I find it somewhat...ballsy...for UA to say I can't upgrade, then offer me a $500 paid upgrade, when they had 80% of the F seats available.
If I had bit, and then saw that 75% of the F cabin was empty, I'd have been one seriously upset elite.
So when it says "no ug available" it probably means there is no NF/NC at that moment. But it should still let you REQUEST an UG one would think.
If there are empty F or C seats, it should. When I saw "No Upgrade Available", I assumed both segments had already checked-in full or had more waitlisted seats then available seats (and even then, they should arguably let you on the waitlist, anyway).
It sounds like the best policy is to ignore the "upgrade available/unavailable" button.
That is what I am now doing. I just call ahead and speak to an agent or ask at the RCC about how the loads look.