Do you know how many millions of Mexicans live in border towns like Nuevo Laredo and Cuidad Acuna? Do you know there are 1,954 miles of US/Mexico border?
For these 2 reason alones, a Buffer Zone would never work.
Well then, enclaves where illegals are detained out side the country an for sure not subject to the wildest defensse lawyer claim.
On capture the illegals would immediately deported to a transborder enclave