On our flight last night from YYZ - YVR, I was in a Preferred Economy seat (my wife took my eUp'd seat)...boarded as part of Zone 1 with her, and there was a lady who boarded behind me and was one row back of me.

As soon as she sat down, she flagged a flight attendant and said she "just got the notification that she was eUp'd into business" (I have no idea if she really "just" got it, or never saw it) and wanted to move up...it took about 60 seconds but they let her move up and the seat behind me stayed empty.

The flight was J0 on ExpertFlyer and the app said everyone had checked in, so I'm assuming someone didn't make a connecting flight...thankfully for her, she boarded and didn't lose.