As a gun owner and concealed carry permit holder for many years, the last place I would ever wish to be is in a situation where I would find it necessary to use lethal force. As such I keep my ears and eyes open and studiously avoid places and scenarios that could bring about trouble. Such is common sense and responsible gun ownership.
George Zimmerman, who is on trial in Florida, would have been wise to follow the above advice in his watch activities. He shadowed Trayvon Martin, a 17-year-old he felt was suspicious looking. My theory is that Trayvon Martin picked up on the tail and took action. The situation escalated to the point where he attacked Mr. Zimmerman, which limited Mr. Zimmerman's options to his weapon.
I believe neither that Trayvon was some thug low-life up to no good nor that Mr. Zimmerman is a blood-thirsty racist out hunting blacks. I do believe that Mr. Zimmerman put himself in a dangerous situation by tailing people in the neighborhood. He should have called the cops and stayed home. In addition, I do believe that Trayvon suspected he was in some type of danger and confronted a person he felt meant him harm.
The situation escalated to the cost of a person's life.
Having the ability and tools to respond with lethal force does not make a person safe. Having the practice to recognize and avoid scenarios that could result in having to respond with lethal force makes a person safe.