I think most carriers flying to the US from YYZ are now padding their gate to gate times to provide a 10 to 15 minute delay leaving the gate at both of the YYZ terminals. This was my experience with the AA LAX flight. I boarded about 5-minutes prior to scheduled departure, and there were still people boarding about 10-minutes after our scheduled departure. We pulled away about 8:05am, as the last of those "stragglers" boarded.

It would be interesting to do a survey here among those flying to the US from T3 or T2 to see if this delay is a regular feature. Airlines would have a resonable idea of their "missing" passengers, and can tolerate such a cushion to deal with the INS/Security fiasco.

Good point about DCA and the additional screening process. And I had forgot that there was a remote set of boarding gates used by CRJs/ERJs at T3 as AC uses at T2 for their CRJ flights.

And note on Fridays, Saturdays and Sundays, there are a few more early departures on JETSGO, CANJET and AIRTRANSAT which go to Florida cities, not to mention other charter operators who fly weekends. All in all, not a pretty picture and AC may have the right idea by moving to clearance upon arrival in Florida.