Some areas have gates that are guarded by cameras and biometric locks. Certain farmers can use these gates at will.
We have been building a fence far better than the Israeli fence. It has cost about $5 Billion and is almost complete. Don't bother looking for it, it's invisible. (Hint: do a FR search for "fence")
Yup we're almost there, just a little more ways to go now and it'll be finished. All we need is a few sensors and it'll be impenetrable. Meanwhile 4000+ per night continue to violate US sovereignty and put strain on our communities and steal jobs from American citizens.
Only a physical barrier like a fence coupled with a strong BP presence will stop intruders. Invisible walls don't cut it.