With a $300 Garmin GPSMap76 and $100 worth of map software I can use my boat's autopilot to steer to within a few feet of my slip from anywhere in the world, even if I had never been there before.

Just making my coordinates available doesn't make me less safe; my coordinates already were available to anyone with $400 worth of GPS and software equipment. The same technology I can use to find my slip in the fog can be used to automatically steer my boat into the heart of Port of Los Angeles. Terrorists aren't looking for the guy living in a home built in 1950 in Van Nuys, CA. They're looking for Port of Los Angeles, where they can make a big splash, so to speak.

Since the target rich world is already mapped and documented within GPS software packages, a monkmap is just a redundant source of already accessible information.