Don’t forget, it’s the longest land border in the world, largely remote. Feels like it would be easy to work around with minimal effort.

Sure, it would be pretty easy to smuggle small, high-value items, but most of the trade volume is in large items like lumber, steel/aluminum, new vehicles, and potash, and it's pretty hard to sneak a dozen 18-wheelers across the border a day. Electricity and oil are also pretty common exports, but those are even harder to smuggle since they go across in fixed wires/pipelines.