My guess is Trudeau will keep the land border closed for a while but will drop the quarantine for air travel for people with vaccination proof. He will rely on the "standard" Europe adopts for proof.
Imagine Europe accepting Americans by plane but Canada not doing so.
But there needs to be a "gold standard" for vaccine proof. Every country will want their standard to be the standard.
Interesting perspective.
If you are correct, then the obvious considerations are the scrutiny that will happen at airports when border security must check proof of vaccination (travelers fumbling through phones, wallets, purses, etc and ensuing arguments about what is acceptable) and what the social scene will look like. Montreal goes into the “green zone” presumably June 28th but even then there will be multiple restrictions inside restaurants.
Personally, I would wait a couple months after any reopening given the anticipated chaos and restrictions.