Designated GUN FREE ZONES are victim-zones. A badly intended person or group seeks out places they can most easily attack and succeed with their attack.
When have we heard of a police station being attacked.
A barking and teeth-fletching dog in front of a house will most likely avert a home invasion while to the contrary an open garage door invites crime and invasion. Think of the USA pre-emptive defense strategy.
This applies to schools and other public places. Criminals know that law-abiding citizens do not bring guns to a place that is designated a GUN FREE ZONE.
This will change certainly, if criminals were to find out that law-abiding and mentally sound citizens participate in their right to carry a 'concealed' firearm of their choice in their own defense and that of others.