Laurence Stein DDS once bubbled...
At the boat show, they said they don't do this anymore. The military GPS signals are on a different frequency than civilian units and are more accurate.
Military Grid Reference System (MGRS) is on most GPS's now along with WAAS.
I'm getting the new Garmin GPS72 (Loran, WAAS, MGRS). My dive buddy has an old GPS12 so the next trip out we'll see what the difference is.