Given how common it is for countries with oppressive regimes to bar or heavily r...

Given how common it is for countries with oppressive regimes to bar or heavily restrict exit, it is noted in article 13 here: https://www.un.org/en/about-us/universal-declaration-of-huma...

The point is if another destination would have you, it is a violation of your right to be unable to freely exit. If hypothetically Canada did not allow you to board a non-chartered plane to emigrate I would argue this would be encroaching if not outright violating this right.