You make a good point, but nothing is foolproof. As I also said there are classified parts to this fence. I could easily write a program to monitor a seismograph to tell the difference between car traffic, tunneling noises, and someone or something actually coming in contact with the fence. I'll bet each "pole" is chipped in some way (that's how I'd do it). Anyone monitoring would know exactly which poles/areas were being messed with. That's why you still need border personnel.
And don’t get me wrong FRiend. I’d like to see a giant 40ft concrete wall concave shaped on both sides, 30 ft into the ground, and wide enough at the top for 4 lanes of car traffic with a mag-lev running in the middle.