In the last episode of , Mark Carroll
said:

"Graham Harrison" writes:
(snip)
Something doesn't feel right in my explanation but based on what I see on
the Toronto Pearson airport website
http://www.torontopearson.com/Connecting.aspx that seems to be the process.

Yes -- admittedly, I don't recall what happened with customs, but I
think I had a Halifax - Boston flight that had me do the US immigration
bit in Halifax on the way out, which was a surprise.

It's actually a bit of a treat, since the US authorities don't have the
opportunity to detain you without access to a lawyer or any of the other
fun and games that US authorities like to claim they can do in the
civil-rights-free-zone of the border, and if they allow to proceed you
regain (some of) your legal rights, otherwise since you're actually on
Canadian soil, Canadian laws will protect you from unreasonable
detention (although you won't be able to proceed on your journey)

--
We have enough youth, how about a fountain of SMART?