With Waterloo, it's more a matter of the school recognizing that the people who will do well in their "prestige" programs (mathematics and computer science, in particular) are not necessarily the same people who excel in getting secondary school marks. I know that my marks (apart from mathematics and sciences) would have precluded me from, say, advanced janitorial training at any respectable institution, but between the math marks (and the contest scores - Waterloo develops and sponsors a number of math contests for Ontario secondary school students), getting accepted to Waterloo's Mathematics Department wasn't a problem (ugh - almost forty years ago now, when co-op was optional and new), where Laurentian was. (For anyone interested, Laurentian University was known for nursing and a unique sports administration program that combined a BComm with athletics, kinesiology and a few other sports-related disciplines. Apart from that, it was known as "the university that had to let you in when nobody else would". It wouldn't let me in.)