The wall would slow them down a little. If they can find a person in Afghanistan hiding in a shack they could find someone climbing a wall with a drone. They also have ground penetrating radar to find the tunnels. There is no excuse for not controlling the border. These people who have all the sympathy for all these immigrates and have them checked out have a short memory. If they could ask the 3,000 people who died on 911 would you like these immigrants check out better you know the answer.