Chief,
The reason for that,and you already know this,is that the "No Gun Zones" are soft targets and the criminal element tends not to obey the laws.

There is a sign out in front of a High School in Texas that says;
50% of our teachers are armed with Glock Model 21s,Care to find out which ones?

I think that does a better job than a sign of a handgun with a slash through it.

Years ago,thoughts of folks doing stuff like this was never heard of. You wouldn't even dare think of it.

I think the old latin phrase Si Vi Pacem,Para Bellum pretty well says it all.

Wayne