That's one of the issues we struggle with, in that there are a number of people waiting to come to Canada legitimately, who have been playing by the rules and are waiting their turn to be processed. There are others who are taking advantage of programs that provinces offer to come forward, and do so legally, whereas others choose to remain after they've gone through a number of processes, or after their legal status has expired, and are in the country and working underground for the most part.
On February 25th, 2008. See this statement in context.