The article suggests that all American boaters have AIS and that "right now some 30 to 40 American pleasure boats are cruising through British Columbia's pristine waterways.". I know the former statement is far from accurate and I suspect the latter statement is also far from accurate.
I see the traffic passing in front of my home, and I often check the boats out with binoculars. I also spent all of July cruising as far up as the passes above Desolation Sound. I saw 1 boat flying a Canadian courtesy flag from the upper staff and had the national flag on the taffrail covered. I saw 1 US home port displayed on the transom, and as we were then in a busy anchorage, the RCMP boat "Lindsay" turned up and had a chat with the occupants, then left them alone. One of our party swam over and had a chat, where it was learned the only violation being committed was failure to register the vessel in Canada, as it was now owned by a Canadian resident. I saw 1 boat large enough to be mandated to have AIS, and flying a US flag. That boat was not broadcasting his AIS, and one of my acquaintances at that location did call the Coast Guard to report him.
Other than those three, all of the boats whose nationality I was able to identify have been unarguably Canadian.
Others who may have violated the "Alaska bound" loophole have managed to do so without straying across my bows.
However, if I do run across an American boater who is in violation, I will certainly turn him in. I don't agree with allowing our considerable, and successful efforts to flatten our curve to be jeopardized by someone from the US, where that curve is more of a spike. The borders are closed for a good reason.