Ben: While Air Canada has always been quite clear that you can't use eupgrades which expire before the flight you're upgrading, and we certainly don't have any "right" to anything else, I'd like to suggest changing this to "eupgrades can't expire before you request the upgrade" in future years, because I think it would be an easy way for Air Canada to increase revenue.

For most tickets, the effect of such a change would be to extend eupgrade validity by at most a week; the only way flyers could "exploit" such a change significantly would be by buying O/Y/B fares -- and Air Canada makes plenty of money on those tickets. Moreover, by being upgraded far in advance using expiring eupgrades, these flights become effectively "inflexible" (since passengers are less likely to take advantage of the flexibility if it will lose them their upgrade) thereby reducing Air Canada's costs.