While I haven't heard of any vandalism there is a number we can call to report US vehicles. I haven't used it, but I have seen a few US plates including one from New Mexico that I took a pic of (but haven't shared it). The vehicle also had a Canadian flag in the back window.
I'm in a tourist spot and the locals have had a few discussions on the matter over Facebook. How many are here because they have Summer homes? (the government says not to travel to them, but if you do quarantine for 2 weeks). How many are here to see family? (the government says not to travel to visit them, but if you do quarantine for 2 weeks) How many say at the border that they're "traveling to Alaska" but are really coming over for a vacation? You get the idea.
They put stricter rules on the so called Alaska bound travelers by putting a dated tag on their vehicle. If you don't actually go where you say you're going I'm assuming you get fined on the return trip. We've also had issues with our ferries as Americans are getting on first instead of residents due to reservations and wait times are insane on top of the ferries only filling at a 50% capacity for distancing reasons. So you can see why some here are on edge.