The changes apply to people who have not been assessed for admissibility yet, people deemed admissible and admitted in Canada can remain for the duration of their status until they seek entry again or apply to change or extend status, in which they'll likely be denied.
If you're a PR you're OK unless you commit DUI 180 days from now, same applies if you have been granted rehabilitation before.
Foreign nationals who have previous DUI conviction, including those who visited Canada in the past, now stand inadmissible indefinitely and must apply for rehabilitation. It also follows that foreign nationals with multiple DUI convictions will stand permanently barred from Canada.
Do I think it is reasonable? Well, I'm all for stricter enforcement and I believe random checks are necessary but this change does not address that it will not change anything about people committing DUI in Canada because nobody can ever realistically expect to do more than 5 years for DUI if they haven't crashed or injured/killed anyone. It will only affect immigrant communities and potentially lead to separating families and deport people who thought they could come here which is unjust in my opinion. You can imagine that a genuine asylum seeker could be deported back to danger in his home country without appeal for having committed DUI 20 years ago, even if that was on a scooter, while a similar person who recently committed multiple violent assaults could remain in Canada. Clearly this does not make sense.
