I agree that immigration needs to follow the correct channels (though I am the grandson of illegal immigrants myself).
But I'm not so sure about overburdening school systems. Schools are paid for by taxes and even illegals are going to pay some taxes. Be that sales tax, or property tax, you can't avoid it.
Plus, I know piles of residential contractors in Toronto who work almost exclusively for cash and pay no income tax. They completely fly under the radar. I'm thinking of 2 in particular. Hell, 99.9% of SPs out there work for cash and pay no income tax. Probably even collect benefits. And we're talking people who are making hundreds of thousands of dollars a year.
And when I think about it, my grand parents came to Canada illegally (bribed a few people, including a priest). They (and my mother) took a lot of shit being labelled as "dirty Russians" (they were actually White Russians). But interestingly, my mother became a teacher and taught hundreds, maybe even thousands of kids to read and write and do math. My 3 siblings and I easily pay over a million dollars a year in direct taxes to the government of Canada. So really, who's to say.