My gun isn't locked up and my ten year old son knows exactly where it is in case we were to ever have a home invasion. Of course, my kid will never take it to school and shoot people because I didn't raise him to be a nut basket.
After the Columbine shooting in which one of the shooters used his grand father's gun, the grand father said he had no plan to keep the guns from his other grand kids. He said he carefully taught the kids how to be safe with guns.
Every time a family dog attacks and kills a family member, the rest of the family says, "I don't know, he was always find before".
Look at the faces of every damn mass murderer and serial killer. I'd bet most people would not think twice about any of them their own kids brought home for dinner.
My point should be obvious but just in case, it is simply this -
We are willfully blind to what is right in front of us.
I'm sure none of the shooter's parents raised them to be "nut baskets" either.