First off these are public schools, private schools can enact whatever gun policies they see fit. And a gun free zone around a school doesn't mean there are "no guns", the guns are restricted to law enforcement. High schools, by and large now, have police in the school at all times. No, it's not going to deter all gun violence in schools. But it would decrease the amount of guns around schools, and have harsh penalties for those caught carrying them. I also feel that when there are children involved, we have to ask ourselves are we okay with the additional risk of a child being injured? I don't care how good a marksman you are, accident happen. The presence of more guns can be seen, especially by children, as the presence of a higher threat. And algebra is hard enough without throwing more guns into the mix.