Being raised in a good home, for sure, does not guarantee a child will not grow up a bad person. I can't imagine that it hurts though. My brother was a prime example till the day he died. Parents definitely need to understand warning signs and realize their child is capable of anything, even bad things.
I'm that guy that would be happy to jump through more hoops to buy guns if it would mean saving just 1 life. Will it fix the problem, nope. But, I do believe it could help certain situations.
In the end, people are assholes. That's why we are where we are. People treat people like shit constantly and it's always in your face with social media. No wonder shit like this happens. I'm sure there are 100's of people thinking about doing this very thing daily, but it never comes to fruition.