I haven't really kept up with Waterloo's new requirements, but this definitely wasn't the case when I was accepted to their Computer Engineering program 6 years ago with mid 80s average with no advanced placement type courses except 2 IB certificate courses (CE was my first choice so I have no idea how SE or ME requirements would compare). They definitely do take extra-curricular stuff into account as well since some of my friends who had averages in the low 90s ish were rejected from the same program.
It's hard for me to believe they've since added a hard cutoff of 95+. It's next to impossible to get grades like that unless your highschool is handing them out like hotcakes at the eventual expense of their own reputation.
That said, the university application process is by no means a stress-free experience for students up here. Getting rejected from Waterloo would have been a huge blow to me at the time because I really wanted to experience their mandatory co-op program and understood the value it would bring to my professional career over the lackluster alternatives at other universities.