I have to wonder what the result would be if the individual land owners were to invest in their own perimeter defense? Triple strand concertina, with flash bangs (Claymores if it were me) as the first ring, then a dead zone of about 50' freshly raked sand, followed by another belt of concertina. Remotely operated miniguns would be really nice for that intermediate strip, but once again that's me personally. If they didn't want to use the electricity to illuminate anything, just solar powered motion sensing IR floodlights would be cost effective, passive, and allow large areas to be watched with just a pair of PVS-7s.
If adjacent land owners then "locked together" with no gaps, they would have essentially replaced the official US border with an effective barrier. Use any available low ground to channel the movement of the illegals, and establish collection points there. Charge the gov't PER HOUR of storage for all illegals collected. After all, the states and Federal government are now using privately funded and operated prisons, why can't We The People? If this were done on a co-op style basis, the locals would then have a built-in business instead of pure liability.