A FlyerTalk Posting Legend
Join Date: Sep 2012
Location: SFO
Programs: AC SE MM, BA Gold, SQ Silver, Bonvoy Tit LTG, Hyatt Glob, HH Diamond
Posts: 44,354
You only show up on the list if you're checked in.
So that fourth person was already upgraded, but hadn't checked in yet.
Checkmarks are confirmed upgrades.