I watched a few episodes of the border show. Boy oh Boy the amount of drugs that come.across and the ways they do it. Tunnels 2 miles long made by engineers, welded panels in train cars, every vehicle panel you can imagine has drugs in them.
Heck they use those ultra lights planes and do aerial drops, then scoot back over the border.
Not to mention the gaggle of people carrying back packs weighing 100 pounds each across deserts that are 120 degrees plus.