I am the mayor of the closest city to the United States, a major urban area on the other side of the border. When the border opens, if it opens later this month, there will be 10,000 people crossing it in the first couple of hours to get their second vaccine, to pick up packages and, most importantly, to visit loved ones they haven't seen in 15 months. Our system will be absolutely overrun. If the thought is that you have to be fully vaccinated plus a two-week window after your second vaccine to be considered fully vaccinated, the system will be completely overloaded at this point of entry very quickly.
On June 7th, 2021. See this statement in context.