It's called gate screening. That was one of the worst ideas TSA ever had, so I'm really sorry to hear it's spread to Canada.

I remember the day I showed up three hours early to get an "A" boarding pass and be first in line on a cross-country Southwest flight with first-come-first-served seating. Those *&*(&*@(! gate screeners not only pulled me and Mr. GradGirl out of line, they held us until every other passenger had boarded. As it happened, the only two unoccupied seats left were together, in the very last row, but I was prepared to pitch a royal fit if I got separated from hubby for a six hour flight because of that ridiculous gate screening. Gate screening has gone away in the U.S., AFAIK.