We walked with them to the Air Canada counter, said our farewells, and dropped our bags at the Vueling counter.
From there it was an easy trip through security. Passengers scan their own boarding passes or mobile phones, the gate opens, and you walk through to line up at the checkpoint with metal detectors and no major hassles, at least for us.
Once down the escalator we looked in vain for Air Canada gates before realizing they were quite some distance.
The tickets we bought allowed one free checked bag each (our rollaboards are heavy) and access to a lounge. This "Excellence" fare also includes priority boarding and extra legroom with a blocked middle seat. It cost very little more than checking a bag so it was a no-brainer.
Our flight doesn't leave until 2:00 p.m., so we have lots of time on our hands and this isn't a bad lounge.