True, it’s kinda hard to come to Canada, to then cross over to the US, so it’s usually people who already are here somehow on visas and Canadians can just get a TN for higher skilled jobs, while low skilled jobs are honestly better off here. For drugs though, majority of smugglers in souther border are US citizens. Most likely in the northern border they are either US citizens or Canadian citizens(since travel is easier than southern border). It makes zero sense for someone who will already go through harsher checks, to also try to smuggle. Cartels rather pay those that can go in and out easily.