I learned something useful the other day. I planned to travel from YYJ to YYZ using an upgraded Latitude pass and get a companion Executive class Aeroplan points ticket for Mrs Canfly15. There seemed to be plenty of open seats at the front and it showed availability for immediate upgrade. Being a (sort of) gentleman, I booked my wife's seat first and there was no problem. But when I then went to get my ticket, it said I would have to be wailtlisted for the upgrade. I guess her points ticket used up the space available for immediate upgrade.

So the lesson appears to be: buy the ticket first to grab the upgrade and then get the points ticket next because SE priority awards should make that available. Moral of the story: it does not always pay to be a gentleman!