system
Given the following post, respond as if you're commenting on Reddit:
human
CMV: Without additional security measures, gun-free zones are completely useless.

Although in general I support less guns on the streets, background checks, and the like, I have always been completely baffled when any location makes a policy that it will be gun-free. For instance, when a location places a sign on the door that no firearms are allowed. What seems to occur is that law-abiding people follow this rule and do not bring guns into that location, whereas a criminal with bad intentions will bring their gun in whether or not there is a sign on the door stating that no firearms are allowed. It simply makes every law-abiding citizen there sitting ducks with no way to defend themselves, making it much easier for the shooter to create a massacre.

That being said, if it is a gun-free zone where every entrance is closely monitored and everyone entering is searched for guns, then this would obviously work and most likely make it a safer place, since the policy of no guns would be actually enforced and all inhabitants of the building have no weapons.

In short, gun-free zones that are not ensured to be gun-free zones by additional security do absolutely nothing to improve the safety of that location. Change my view.
gpt
Your point is perhaps effective if only considering mass shootings. A lot of gun violence doesn’t involve someone specifically looking for a large, vulnerable gathering of potential victims. 

A place designating itself as gun free allows them to enforce the prohibition of guns in their venue. Absent some sort of enforce mechanism this might not stop a terrorist, but it might allow them to ask someone to leave a bar or a concert or classroom and return without a gun, which could then prevent an unplanned instance of gun violence resulting from, say, an argument or altercation.