Trouble with measuring crossings is it picks up an aggregate of things; Canadians crossing for leisure, for business, Americans crossing for leisure and work, medical tourism (Americans coming for insulin, my uncle driving to Mexico for dental care, etc.), foreigners on a road trip, people driving between Canada and Mexico, etc. Most of these are round trips too; you're going to be measured coming in and then out (so you're part of both statistics).
This sets aside people who already had non-refundable bookings from a year ago; Disney essentially let us cancel our Florida trip once they confirmed our French reservation at Disney there; sure, it's still money going to Disney, but at least a lot of that money is being divested into the French market instead.
My friends who weren't able to cancel made a point of limiting their spending while they were there still. And then there were a couple who just didn't care as well.
Ultimately, the metrics (and their sustained impacts) will be an aggregate of many things, and eventually Canadian fatigue as well.