The reason you may not notice UA staff taking down your DinersML or Aeroplan number is likely because you are flying on a UA flight. In my experience, they do check boarding passes, and if you are not flying UA, they do take down your card number. As does AC or LH when you are flying a STAR carrier other than themselves. Since UA charges for alcohol, they are not overly concerned with billing the STAR partner when one is flying UA, but only when one is on that, or another, STAR partner flight. I have, otherwise, always had these details written onto a sheet maintained by the receptionist at every lounge I have visited.

As for the cost of program miles, the generally accepted internal measure is the 1 to 2 cent per mile US, so the ready dismissal of 1-cent Canadian is imprudent. And as Aeroplan becomes a distinct entity, real dollars will be exchanged between AC and Aeroplan, making this a very real cost to the carrier which does come off the cost of a ticket.

SouthWest has a basic seat pricing formula, no interline or other heavy infrastructure cost, flies point to point. This is the model used by new starts, and for that reason it works well and lets them make money. But since more than one-half the passengers on most full service carrier flights will be connecting to other flights, online or offline, costs per segment must be separated out. And routes that are flown may in themselves not make money, but do feed traffic into the mainline ones that do make money. This becomes a very complex system, and if it were just AC that was unable to make a profit, I might agree with some of the comments here. But it is the models that give the results we are witnessing in the industry. And why AC continues to differentiate brands and products [and business models] in its restructuring.

As for my choice of YYZ-LAX, we could just as well substitute YYZ-YYC. The only difference would be the reduction in half of the cost allocated to Aeroplan. All the other infrastructure would be similar, so competition is only a factor insofar as giving 50%, 75% or 100% Aeroplan miles on a given route.

Returning to SouthWest: it also has a very simple FF program and aforementioned route structure. It is not a major issue if they give a seat away, since all seats are priced the same. If there is an empty seat, maybe it can be redeemed. But how many exotic destinations on the carrier are there? I would rather do Hawaii than Houston... It has no upgrades, so it has to offer less stringent redemption practices to make up for what it lacks in other areas.