I'm with Excaliber on this. Elsewhere I posted some stats developed from 104 active shooter events from 2000-2012.Excaliber wrote:...
The short answer to your question is: yes, the signs will have the intended effect.
... the one common element in their go / no go decision making is: Will I have five to ten minutes of unopposed killing before police intervene?
Unfortunately, the study does not directly identify which events occurred in "no gun zones," but most of them occurred at businesses (40%) and schools (29%). I think it is a safe bet to say a large majority of the businesses (especially for employees) and all of the schools were "no gun zones." I think further supporting evidence for this is that would-be victims stopped the attacker only 17 times, and only three of those were by gun.
Just over half the time (53 times), the shooter did not stop until police were on scene (and I would wager that only then did the shooter encounter any significant resistance). Then the attacker was shot (23 times), committed suicide (15X), was subdued (9x), or surrendered (6X).
The median response time for police was 3 minutes (median only 2 minutes when a single officer intervened); police were on scene in about 3 minutes for the five events with the highest casualties.
The single largest "end" or "resolution" was when for his own reasons the shooter decided to end things by killing himself before police arrived (29X). Only five times did the shooter just leave before cops arrived.
So I think all this points toactive shooters gravitate towards places where a lot of unarmed, unresisting people are going to be easily found. A sign promising resistance is not going to be absolute defense, but I think it will discourage at least those active shooters that don't have any connection to the place (45% of the ones in the study) and some that do. For this type of event I don't think it has any significant downside.
I think these statistics also point to the fallacy of locking guns up someplace where a teacher/staffer has to move to get to it and then manipulate a lock. The response needs to be RIGHT NOW.