Gotta correct this because this is misinformation....the 3 schools with rigid cut-offs are Ottawa, Queens, and UWO. Ottawa - weights your GPA with the more recent coursework getting more credit (e.g. your junior year grades will be weighted at 3x the value of your freshman year grades) - so definitely encouraging of the upward trend. And if I remember correctly, their cut-off was 3.83 for non-Ottawa Ontario residents and something like a 3.89 for non-Ontarians. Hardly a walk in the park.
Queens requires 3.78 in your 2 RECENT years if you can't meet the overall GPA cut-off of 3.68 (pretty high as well - above the average admitted GPA in the US, for sure). The fact that it's 2 recent years is also definitely in favor of the upward trend.
UWO is 3.7 in your BEST 2 years, however, they do evaluate your entire academic record once the cut-offs are made and the automatic interview offered, so your entire academic record still bears an impact on your admission.
All other schools also use the 2 best years only for cut-off purposes and then look at the entire record for interviews and/or admissions offers, like U of C, for example, or UBC, which looks at your cumulative GPA AND the last 60-credit GPA, so again, encouraging an upward trend.