I’ve always thought that there should be guard towers or miltitary like post stregically placed every so many miles along the boarder. Much like the Chinese Great Wall had their posts built into the wall. I also think that border satellites should be a part of guarding from the sky. If they have the technology to know where the pools of oils are located in the ground and other anomalies I would bet they could find tunnels and heat seeking technology to know where the bodies are who are out in the wilderness areas about to cross. The border control agents could be there in a better response time.