I heard about this on PodCacher a while back. I didn't quite follow their explanation of it, so this article was helpful to me for a better understanding. Actually, anyone could do this with any geocache, if you could find a GPSr that only had a readout of distance and no directional arrow or map!
"Wildness is a necessity." -- John Muir
"When you go to hide a geocache, think of the reason you are bringing people to that spot. If the only reason is for the geocache, then find a better spot." – briansnat