Unfortunately as the population increases your going to see more and more. If the chances of someone going crazy and doing that are one in a million and your population increases from 10 million to 20 million then you have doubled the number of people who will go crazy and do something like that will increase proportionally.
I'm betting we will see more anti laws passed as well which won't help any more than all the previous. My small town country school brought in someone for a hunters safety class, and in history class one of the teachers brought in various rifles from an old black powder to an M16 and shot blanks for us to 7th grade when we shot .22's in gym class. Of course the teachers all ran over to help me thinking this smallest kid in the class couldn't hold a rifle so I had to explain to them I was just turning it on its side comparing the bolt action to my semi auto at home not having trouble holding it. Then he county consolidated us to a big school where guns weren't talked about and my senior year a girl got show and killed at her boyfriends house when her ex shot at her current and missed. Then I move to the city and my wife's school taught her than guns are bad and they had regular shootings where she had to duck and run when one happened in the hallway she was in. I find it ironic how those laws have the opposite effect. IMHO there should be a field trip to a shooting range should be required with a safety class showing some damage from accidental shootings so the studnets can see what a gun can really do and get a little respect.