Pleasuredome,
Your idea is severely lacking in humanity, creativity and CLASS. You make it sound really easy to shoot at a woman or a child. Do you think that a true warrior would do such a thing for his country? Do you think you're tough enough to even pick up the bodies? I must say, pink suits you very well.
Given that this is a forum after all, I should realize that he's only saying this because he's hiding behind a PC. So I'll leave him alone.
I believe, that a MORE HUMANE SOLUTION would be to track immigrants biometrically. A chip can be inserted in their finger which can be tracked by a global positioning system. It's already being tested in some U.S. prisons with great success. It's already available here to track lost pets and it works very well.
Legal citizens can be given 'smart cards' which they must carry at all times. These smart cards are nearly impossible to falsify given the technology that they're based on. Once all citizens and immigrants have been identified, we can implement technology which will help us protect the borders (drone aircraft, heat sensing/ultraviolet rader systems etc).
It's an advanced approach requiring a large financial investment, but mark my words - it will happen.