In essence people using this map were warned that it was unsafe to walk around in the city, and it was suggested instead of walking one should use the collective transport system or taxis.
Below this strange statement the company producing the map had added that they were forced by the Mayor Ms Feinstein to print this advice/warning on all their maps. However, in their opinion it was not up to the Mayor to decide what to print or not to print but to work to make it safe and secure to walk about in SF at all times.
I thougt that was very well stated and I used the map to guide me as I walked around in the town. I understood that Ms Feinstein was a total moron and ought not to be elected to anything apart from possibly junior-substitute dog-catcher.
Unfortunately the good inhabitants of San Fransisco /California have not come to the same conclusion - yet!
The reason for the disclaimer/warning is the tourist especially the unaware foreign tourist has always been a delicacy for street ferals.
That was Feinsteins’/city governments way to compromise short of a more direct warning as the tourist trade may suffer. Any individual hurt is acceptable damage so long as the money flows unless the incident is so bad it can't be covered up.
Case in point a German women cut down in a crossfire in Union Square. The tourist angle was downplayed as the women wasn't the target.
http://www.thelocal.de/society/20100810-29049.html