I travelled up north last week to take Hwy 2 into MT and on the drive up I saw not only commercial vehicles traveling south with AB license plates (allowed) but also what looked to be personal vehicles (4-5) with AB plates on the vehicles. I think I mentioned to my wife that as far as I knew the border wouldn't be open for a while yet and what was the deal with, what looked like personal vehicles traveling through from Alberta? Not that I personally care, but was curious...perhaps they had a good excuse! No BC plates were spotted and they're usually more numerous in the area than AB folks are.
On another note, when I've traveled to SK to goose hunt, going through Canadian customs is generally much more pleasant than coming back to the USA. It seems the agents at the small USA border crossing need to be dickheads to feel they're doing their jobs! Of course, covid-19 wasn't present this past October when I was last in Canada, so It's probably changed a bit.