Great point! Our countries are about the same size.
What's funny about this thread is everyone complains about this yet no one can offer any real solutions.
There are only two solutions. You let them in, or you keep them out. Now whether it is a wall, a fence, pilotless drones with sleep agent, whatever, there needs to be a solution.
Point is the Israelis threw up a hundred or so miles of fence in what, 16 months? People want money for college? Hey, work six months on building a security fence and the government will pay you for a year in school. Build a dozen outposts along the route where workers can sleep, eat and rest. Make it modular. When that part of the fence is done tear it down, move it and set it back up. When you get to a town, make that a border crossing.
It will cost some money, but in the end it is worth it.