Originally Posted by
Kacee
It's very common for UA not to run any sweeps before T-24. Just ran into this the other day . . . 739 was booked 9/20 in F, no sweep until T-24, when I and 8 others cleared. Flight wound up with a bunch of names on the waitlist. I would guess they cleared GS, 1Ks, and maybe some Plats, leaving lower fare Plats plus Golds and Silvers still listed.
I assume you checked it was PN0 for your flight until the sweep — is that why you say it was also GS clearing at T-24? My recent experiences have been that, when there is a lot of unsold space, it has been PN>0 from at least T-120, but it stays PZ0 until T-24, when it may do a sweep as you describe.