true on all counts.

About uograding passengers before denying boarding - I’ve even been op-up’d before - both as an elite on UA prior to UDU starting, even as a silver, and after on an award ticket where I wasn’t eligible (I have a UA card, but it’s legacy so doesn’t have the award upgrade benefit). In fact, the latter situation happened in Dec. so absolutely they will do it. Even on long-hail. My wife loves the story of being on DXB-IAD (yeah, was a while ago) - at the gate, they called her up with a new BP and she was upset they changed her seat - until she actually looked at it and saw it was in Business. Other airlines do it too - a year or two ago I was on FRA-BLR around Xmas time and got what I considered a double-upgrade from Y to C. Was a great flight. And while these do happen - they are rare. More often what I see are flights where F starts empty - looks like a decent shot at CPU at booking - but then F fills up - either slowly over a few weeks or its mostly open one day, then full or close to it the next and goes out with 0 upgrades. That’s what’s supposed to happen - airlines try to match seats available to demand, and sell everyone of them. They aren’t putting extra F seats on planes specifically to give them away for free - they are trying to sell them. But demand fluxes, and they can’t always get it right - so they decide to give away what they can’t sell to elites. It’s a good - but you have to understand what it is there for, and you won’t be disappointed. I definitely appreciate an upgrade when it happens, and look at the lists, try to book flights that look better, etc. but I don’t see it as an entitlement - If I get one, great - if not, that’s great too (after all, I’ve already got what I paid for). Especially these days, it’s a good outlook to have, since there tend to be less of them, and I don’t get them as much (due to lower status, typically traveling in a party of 3 these days, etc.)

I agree with you that in my experience on UX only I will generally clear exactly at the Plat window with seats avail, and that almost never happens on mainline (which is what you were saying!). I suspect in this case though, that just didn’t happen. Nothing out of the ordinary, just an unusual amount of last minute purchasers of F. The internal algorithms must have foresaw this and therefore restricted the upgrades at then Gold window.