That seems to me like a potentially huge change to anarchy play. I can't quite decide if it's better or worse - there is a part of me that likes the idea that a map of your area could be used as an "early detection system" to warn you of encroaching PCs. With FC's change to maps where it would only show PCs moving above ground, this could even be an interesting mechanic whereby players are encouraged to stay underground near suspected PC bases to stay "under the radar".Players see other players moving around on the same map
On the other hand, it turns maps into a magic radar device, and that is kinda lame from the get-go.
Also: does anyone know if "on the same map" means "within range of the map you are holding" or "holding a copy of your map"? The second is less of a radar but potentially cool for anarchy-alliances.