The idea behind this legislation is admirable, but there is a cheaper alternative. Two parallel wire fences 10 meters apart can be constructed along the full length of the border. If the space between the two fences is sown with tessellated land mines, that should deter unwelcome guests.
Seriously though, do we really want to keep them out? The current labor force is too small to keep up with demand. If we clamp down on immigration we will inevitably drive up the cost of labor and initiate an inflationary spiral that we will regret. Of course, it makes more sense to increase the allowed level of legal immigration than to encourage the illegal kind.