I've driven in Mexico on a number of occasions: from Laredo to Tampico and back and from Acapulco to Mexico City. It's scary. They pass blind around curves. They drive at night without headlights. In Mexico City, everyone is oblivious to the lane designations.
Now, in addition to bringing their job skills, they're bringing their driving skills.
Multicultural response: Wave them on in, retrofit your vehicle with tank siding or surround your car with tires to absorb collisions, double every type of insurance you can, put a Blessed Virgin figurine on your dashboard and a hula dancer in the rear window, and pray hard.
Sane response: Close the borders and start deporting.
funny how the "sane response" is the ONLY one the gov't has not tried yet......I'm sure they will get around.