Given that the USA refuses to make firearms freely available to its citizens, there needs to be mandatory training in firearm safety there.
Unfortunately, we are exposed to TV programmes and films where it's safe to (for example) hide behind a car door or a wooden desk in the face of gunfire. There needs to be education in the real power of these weapons. If the two people in the story had seen the real penetrating power of a bullet, I'm sure they would be neither dead nor facing prison time now.