The government's plans to put a hi-tech "virtual fence" along the U.S.-Mexican border has been put on hold.

The theory was that towers, technology and computers could replace the need for an actual physical fence, but tests on the virtual fence sometimes confuse raindrops and bushes for people.

One border agent saw a group of 80 illegal aliens with his own eyes, but found the technology missed them all.

The government had hoped to have the virtual fence covering its first hundred miles by year's end.

That date's been pushed back to 2011.