Originally Posted by sexykitten7

I'm not sure [MENTION=872393]jm0933[/MENTION] is so far off.

Anecdotally (and this is pure conjecture) I believe that checking in early can improve one's chances.

One memorable case was back in Feb 2016 I cleared DEN-DFW on an A319 on a Saturday at noon as a Silver on an N fare pretty far in advance (12 hours?). That alone, is remarkable considering that a/c only has 8 F seats! There were probably 8+ ppl on the upgrade list when we took off. Surely there weren't 8 Silvers on an N fare on a Saturday! The canonical explanation is they were all non-revs or late SDCers. But the noncanonical is I actually skipped higher elites based on my early check in (well in advance of 24 hours). That is, the computer was actually clearing pax out of order. Yes, it's controversial to say that but it's just a feeling, not a scientific fact. Back then I didn't know how to check for non-revs or else I would have. I caught 3/4 upgrades that day but that was the only cleared flight with a weirdly long list!

Unfortunately since the process is so opaque, there's no way to know the instrument, status, fare, and check in of each person on the list! That would solve a lot of our headaches!