And they use those tunnels. Don’t forget the tunnels. Plus the areas away from population where they use ladders. Fences are only as good as they are supported by people, if not supported they’re just a nuisance that will be gotten around or broken through. Which isn’t saying we shouldn’t have it, simply pointing out that a fence is the BEGINNING not the fix.
Here is what the border patrol says about fencing here in San Diego.
Today, Henry is assistant chief of the Border Patrol's San Diego sector. He says apprehensions here are down 95 percent, from 100,000 a year to 5,000 a year, largely because the single strand of cable marking the border was replaced by double — and in some places, triple — fencing.
The first fence, 10 feet high, is made of welded metal panels. The second fence, 15 feet high, consists of steel mesh, and the top is angled inward to make it harder to climb over. Finally, in high-traffic areas, there's also a smaller chain-link fence. In between the two main fences is 150 feet of "no man's land," an area that the Border Patrol sweeps with flood lights and trucks, and soon, surveillance cameras.
"Here in San Diego, we have proven that the border infrastructure system does indeed work," Henry says. "It is highly effective."
http://www.npr.org/templates/story/story.php?storyId=5323928