I guess
I don't see how this genuinely improves anyone's security. Let's start with the mundane: Are you worried that you will get mugged or carjacked while on your way to school? I'm going to assume that the odds of that happening are quite low. I'd further say that the evidence shows that firearms rarely stop crimes (e.g.
http://vpc.org/studies/justifiable15.pdf).
I can see how rural residents might find firearms more useful, as police response times in those areas are surely much lower. At the same time, crime rates are also generally much lower in rural areas, meaning there is less need. In fact, death from accidents is a much bigger issue in rural areas than crime, and owning a firearm obviously increases the chance of a major accident. Similarly, simply bringing a gun into the school obviously risks a gun-related accident -- and yes, those kinds of accidents definitely happen in schools where staff can carry firearms. On the whole, it's probably not worth it.
Moving on to the less mundane -- i.e.
extremely rare -- school shooting scenario, a firearm seems like, well, the kind of macho thing that will cause more problems than it solves. To start with, chances are you'd have to pull the trigger on a student you know, while other students might be running around and into the line of fire. While being a badass may seem easy in your imagination, I suspect it's going to be incredibly difficult in the moment. In which case, you are making yourself a big target.
Even without that particular quirk, it is very very rare for an armed civilian to stop a mass shooting in progress; in most of those cases, the civilian is actually an off-duty or retired police office.
I suspect that much of the reason, as already hinted in this thread, is due to training. At the risk of stereotyping
most librarians I know have not had extensive training in live fire situations. Schools and states, as far as I know, don't have a solid training program either. (Even if you did have training, a) you'd need to constantly refresh your skills and b) training is not the same thing as actual experience.) It certainly isn't part of the Library Science curriculum....
This is why the expert advice for mass shootings is "Run, Hide, Fight." What you should be doing is either getting the students to flee the school, or helping them hide. (Obviously, if your school has a policy, Taking on the attacker should be your last resort, and having a gun in your hand may tempt you to think "Fight, Fight, Fight."
Another consideration is that you can get yourself into trouble. On the mundane side: Obviously, if school policy doesn't allow you to have a concealed firearm, that's a big issue. If for any reason you put your firearm down, that can cause an accident. Or, in what is admittedly a rare circumstance, you might be tempted to brandish your firearm in a situation that doesn't require it (e.g. a confrontation with a student).
And if there is a shooting -- again, that is
extremely rare, and not happening at higher rates than in the past -- when the police eventually arrive, they aren't necessarily going to know that you are a Good Guy With A Gun. To put it mildly, this will complicate things during and after the shooting episode.
Overall, I don't think it enhances anyone's safety. I'd pass.
