Originally Posted by
findark
Likely (a) was ahead of everyone and they checked in when they arrived at the airport between T-60 and T-30 (minutes). Also don't forget any of those pax could have been 1Ks on M fares, or other 1Ks with instruments ahead of you in addition to GS.
Or the "upgraded" mystery pax may have purchased an upgrade that booked into PN or R.
Bottom line: there are multiple possible explanations for this.
I cleared a CPU two weeks ago at T-3 without having checked in yet. So my name would have "mysteriously" appeared on the upgraded list despite never showing on the waitlist.