Apparently this started a few months ago but I just noticed it now. Oops.
Air Canada has a promotion for travelers between Montreal and Toronto’s City Airport. Lasting through the end of 2012, customers on Latitude fares (not the cheap ones) will earn an extra 50% elite qualifying miles for flights between the two airports.
No registration required to earn on this promo; just show up and fly.
Clearly trying to pull business from Porter Air on the route. Competition is good in this case.