Yes and this is what worries me. I have been traveling a bit these past few months and it has been domestic to international connections and at the departure point they never checked my carry on. At the long haul international flights I have never seen them check at the Gate either. Last month I had to do an overnight in YYZ and as I was going thru to security one AC staff told me that I had to show my carry on to the staff near the machine but once I got there she had a look at my BP and waived me on. That said mine is not that oversized and I have been using it for the past 4 years now without any issues but never got the opportunity to check in on the sizer without anyone noticing it.
End of the month I have an overnight in YYZ and need to check in separately for the domestic flight. I have no worries in checking it for the final domestic sector but for the international flight it would be an issue for me.