Well, bear in mind that CP staff were still operating CP systems on CP equipment. That hardly demonstrates laziness on the part of AC staff--it demonstrates two different systems handling two different sets of people.

For all we know, AC cancelled a previous YOW rapidair, and had a hundred extra passengers on its hands.

AC does have an established method of clearing lists.

1) Must Rides--deadheading crews, etc.
2) Revenue pax confirmed on the flight
3) SE/EP in order of checkin
4) E/G in order of checkin
5) P/C in order of checkin
6) non-status pax in order of checkin.

RESIII clears all standby lists after the flight is closed, and the flight is under gate control. To do otherwise would cause problems for revenue J/Y seeking to rebook onto earlier/later flights. If standby lists clear early, then you have wind up shutting out a higher priority, revenue passenger. Also, you run the risk of shutting out a last minute SE/EP in favour of the earlier E.

Standy is precisely that, standby. The computer clears those lists pretty effectively.