Many (hopefully all) of the opinions expressed in this thread come from (hopefully) sane, reasonable members here. So they sound like just good sense to me. The problem is we non-crazy minds are trying to understand the thoughts and motives of some pretty crazy killers: we have little hard data to help us do that, at this point. The assessment or prediction of threatening behavior and who will become violent toward others is imprecise and subject to significant error. At this point in the scientific understanding of these issues we are guessing, and there is currently no unchallenged data regarding the factors which increase vs decrease risk. I'd like to take some comfort in the assumptions that allowing CCW and elimination of no-gun signs would dissuade deranged killers, but I can't. Perhaps armed citizens could quickly kill the killers once they got started on their spree - but would we prevent them from getting started?
No one here is trying to predict the exact actions of a madman, nor do I see any claims that there is a way to consistantly prevent their actions. There are just a few common sense traits that are present in human beings, one of them a tendency to go towards the path of least resistance. If you are selecting a target for high body counts you are insane, but not necessarily stupid....lowest on your list will be a gun range, a police picnic, a military live ammo drill. A bit higher might be a bank or a shopping mall (there might be an armed guard or CCP individuals there). Next level might be a school or a theater...but which one? If there was a choice between one that advertises that it allows CCP guns, and one that posts a sign that it bans guns, that target is softer...an easy choice.
No one could prevent the start of carnage, but a couple of CCP in the crowd and well placed shots would end the madmans murderous rampage before he could kill everyone. It may also give publicity-seeking copycats pause.
The Internet is brimming with studies, articles, and anecdotes, as is every back issue of
American Rifleman, backing up much of what has been said in this thread. Bringing it all to ETS requires more time than I have right now.
John Lott is a gun expert, I am not. You might begin your research with this article and others by him...
http://www.press.uchicago.edu/Misc/Chicago/493636.html/