This one? "(addon) When figuring No-Man's Land, are they actually overlapping Setup Areas or just distance? For instance, O12 is not Enterable to the Japanese but is within 2 hexes of Strategic Locations on both sides."
From Z4.2
Setup Area: Each Strategic Location Controlled by a side, plus each non-Strategic Location within two hexes of an enemy-Controlled Strategic Location (i.e., not a No-Man's Land hex; 4.7051). Each such non-Strategic Location hex must also be Enterable by Infantry from >= one Strategic Location of that Setup Area.
No-Man's Land: A non-Strategic Location within two hexes of both friendly- and enemy-Controlled Strategic Locations; 4.7051.
4.7051 says "As each side determines its Setup Area(s), there will be portions of the map where two opposing Setup Areas "overlap." A non-Strategic Location within two hexes of both friendly- and enemy-Controlled Strategic Locations is a No-Man's Land hex. ..."
To be in a Setup Area, it must be Enterable (and the stream hexes are not Enterable) so O12 isn't in any Japanese Setup Area. Therefore it isn't technically overlapping with the American Setup Area, but it is within 2 hexes of a Strategic Location. The definition of NML doesn't seem to require that the hex actually be in any Setup Area.
So does distance (within 2 hexes) trump being a hex within the Setup Area of both sides. The answer appears to be yes. One can create a NML hex even when one or both sides can't actually claim it as a part of a Setup Area.