A “border watch group” in Arizona is proposing the installation of underground sensors that will listen for the footsteps of illegal immigrants crossing from Mexico.  They’ve apparently gotten the ear of an Arizona state legislator, who says he’s earmarking $5 million of existing funds to install a 5-mile prototype of the system.

The system, which has been promoted by the group American Patrol, had received some regional press last summer, but was first featured nationally this week by the new Rupert Murdoch iPad-only publication, The Daily, which reports that the sensors would be buried up to 12 feet underground, and are designed to distinguish a variety of activities, including individual people, groups, vehicles, animals, and “likely tunneling.” An American Patrol posting in late January had announced that “We are testing the system now and expect to make a major announcement in late February.”