Well, I was in Montréal for the Memorial Day Weekend. I spent 20 minutes in line at the airport to buy the ticket (Sat., May 29th, approx. 10AM) and the buses were running full. Fortunately I didn't have to stand on the ride, there was also traffic into the city that morning, it took about 45 minutes to get to René Lévesque and Peel (I was at the Marriott Château Champlain). The return ride on Monday (May 31st, around 11AM) was standing room only by the time we got to Lucien-L'Allier, also this bus was a regular one without luggage racks, people were falling over the place.