I'd be very surprised if the Canadians don't have spies in the US, but this is exactly the issue that's been eating at me from the beginning. What would an illegals program give the Canadians (or anybody else) that a regular spy wouldn't?

It seems to me that everything we see on the show can be done just as well by a regular spy whose family lives back home.

Pretending to have a back story - like when Stan talks about where he was when Kennedy was killed and P&E join in - did they really need to live in the US for 20 years for that?