Ah, yes...another possibility. The Mexican guys are, however, among those people who basically get either overlooked or ruthlessly exploited by the powers that be (in both Mexico and the USA). Illegal immigration is mostly driven by desperation and economic privation. Most people would happily stay in their own country of birth, provided they could find safety, security, and a reliable means of earning an income there.

If you want to end illegal immigration, you must end dire poverty, cruel dictatorships, and gross inequality on this planet.