Simple logic will advise that a criminal is a person who does not obey laws.  Therefore, laws designed to limit the activity of that criminal will ipso facto fail to acoomplish the intended purpose. An individual intent on mayhem will not be deterred by a posted sign. It further follows that an unintended consequense of the ineffective law will create a location where there is no defense against the armed criminal because, by definition, law abiding citizens will obey the law and be unarmed, and therefore defenseless.  I hope that the logic of this argument, often made before, is clear.  It should also be obvious, that the people who work in these gun free government locations are placing themselves in a dangereous location because they have rendered themselves defenseless.  That is, of course, assuming they obey their own prohibitions.  Gook luck with that!