Licensed -- and unlicensed -- carry
An earlier post drawn from a book by Chris Bird gave information from 2007that there were 3.4m persons with licenses to carry in the 38 states with "right-to-carry" laws. This is about 2% of the population of these states (197 million, about 2/3d of total US population of 303 million).
If we assume 1% (1.1 million -- it is probably less) have been given discretionary licenses in the 11 states without right to carry, there are a total of 4.5 million Americans with legal licenses to carry.
These people are straight shooters in at least in one way: In a study of data for 1996-2000 Bill Sturdevant found that the general population of Texas was five times more likely to be arrested for violent crime that license holders and 13 times more likely to be arrested for non-violent crimes than license holders.
But licensed carry is only about a quarter of the whole: Surveys in 1993 done by a Florida professor (Gary Kleck) estimated that there are 17m people, about 9%, of the US population (in 1993) that carry guns for protection on their person or vehicle.
Therefore, there must be about 12 million UNLICENSED people in the United States who carry outside the home on their persons or in their vehicles. These people must be --
1. The bad guys
2. People avoiding the cost or hassle of registration
3. People who believe that the Constitution's statement that "the right to keep and bear arms shall not be infringed" means exactly that, that registration does infringe and may lead to confiscation (as in Britain).
These last two groups must be trading off risks, that of fines/jail for illegal possession vs. that of losing their lives in a violent confrontation before help arrives. Another author (Andy Stanford) states that even an untrained assailant can fire up to four rounds in a second and, knife or club in hand, can cover 7 yards in 2 seconds. This recalls the familiar lament: "...when seconds count and the police are minutes away..."
Obviously each person has to make their own decision about carry and licensing -- just make sure you don't give up even a fraction of a second thinking about it during the action confrontation.
Or maybe you just following the kind of policy they might come up with in San Francisco: "Citizens who are killed by a criminal must immediately notify the police."