I told this story already on the other, more reasonabley titled thread "Plane Crashes Into Tampa Building" but maybe it fits here too.
"When I was in flight school we had a guy flip over a love gone bad, and "tried" to kill himself a number of times over months. We reported his suicidal behavior and got his medical pulled. It was a tough call for us to report him, because we did know it would ruin his career in aviation and he had made no actual threats to do something like this. We just thought he may decide his other methods were not working."
I don't know if we prevented anything or not! But we were nervous seeing him around the flight line knowing that the weekend prior he had slit his wrists in a friend's dorm room, or tried to gas himself in his car.
I guess I wish that those around this kid had been thinking. It would be rare for this act to have been the first sign of trouble, but maybe. Those around the school shooters have often had better hindsight than foresight.
Instead of being smart and observant of those around us, we instead often see reactions that try to treat everyone as a potential threat, spawning "zero-tolerance" rules that get girls kicked out of school for having nail files, and confiscation of swiss army knives at airports. the "success" rate of 9/11 had nothing to do with the weapons used.