>>Looks like they are going to wall off the whole Yuma Sector of the border, except perhaps a few miles SW of town, on the Cocopah Indian Reservation.
I bet they significantly up the electronic surveillance there.
I think so too. You would probably only need one tower on their land. The really big Reservation on the border (also in Arizona) is the Tohono O'odham Nation (TON).
They (TON) voted to get Integrated Fixed Tower (IFT) coverage of their border with Mexico (>50 miles), and it is already funded and on contract. They have a significant problem with cartels running drugs through their territory, and trying to corrupt their members.
The Cocopah Reservation may already be included in the big IFT rollout for Arizona - over 200 miles contracted. Even a couple of the new mobile surveillance units could provide strong oversight of a few miles - technology and freed up Officers will converge on the remaining gaps. These mobile units can pick out the heat signature of a kid under a bush from miles away:
Even more than the Tohono O'odham, the Cocopah may end up wishing for barrier later, if they don't get it now, because a lot more traffic will be funneled through a much smaller gap.