Aw, yew bet! But ya see, I live on an island between the BC coast and Vancouver Island and the nearest things we have to illegal aliens is a couple of geriatric American draft dodgers.
The point that you missed is that most illegal immigrants in the US didn't wade through the river with their clothes bundled on their heads, they crossed legally through customs checks and just stayed.
You want to make a dent in illegal immigration? Go to the source- start busting the people luring them into your country, the people making big bucks off cheap labour. Jail a few golf course operators, sue a couple landscaping contractors into bankruptcy, shut down some hotels and you'll see, the rest will stop hiring illegals and the illegals will stop coming.
It's the same as the drug trade. You can't ever shut down the supply as long as there's a demand.