Well considering that Pierre of the NRA thinks it was fine that my kids were exposed to guns, but I clearly screwed up playing video games with them, I'm not sure logic is in real high supply right now.
Remember "X-Boxs don't kill people, people do!"
Exposing kids to guns and teaching them the responsibility of owning or handling a firearm will do them far more good than bad. Shield them from firearms and see what happens not if but when they come in contact with one: the odds of them totally and completely disrespecting that responsibility will be lost.
Exposing them to the glorification of any violence as we see on CoD, BFx, or any other FPS and not taking the time to explain the ramifications of being able to "re-spawn" after getting killed (or killing) in a video game vs what reality is something not to be taken lightly.
If you or anyone else thinks that guns are able to pick themselves up and do evil then I'd like to know how so I can watch it sometime. None of the firearms in my gun safe have ever killed anyone (safe for perhaps a very well worn Japanese Arisaka chambered in 6.5mm Jap built in 1932). The fact that there are fewer guns per population and per household now than there were in 1900, the fact that there are far more laws restricting gun ownership now than there were 20 years ago, and the fact that it is harder to obtain a firearm today than it has ever been thanks to a NRA devised background check tells me one overlaying theme: it isn't the guns. The bad guys, the psychos, the religious zealots, and anyone else who wants to harm the masses will get the job done with or without the use of firearms (anyone remember a certain Tim McVeigh? Anyone?). The best thing we can do is to stop them before they get their first shot off and that is done with secured entrances, security cameras, and the ability to stop the threat by equal means and if that means allowing the admin, the teachers, staff, or any other volunteer to arm themselves then so be it.
FWIW, back in 1991 when I was a jr in high school we had a project for speech class that entailed a "teaching how to" in front of the class. Guess what I did??? I took a shotgun to school, with permission, and taught the class how to clean a shotgun. Per the principle's request, I had to remove the firing pin and not bring any ammunition to school. No problem. The Remington Mod 11 (Browning Auto-5) stayed in the Mr. Hannah's office until class time and he brought it down to the classroom it the case. He walked in, handed it to me, then walked out. I did my presentation (I earned a B), then walked the cased shotgun back down to his office. Why was it different THEN than NOW? What has changed? The root cause of our problems do not sit with an inanimate object.