I like to think of issues like this in the same way that I consider discussions of smoking, alcohol, and legalized drugs. In short, alcohol is very legal in this country, but there are VERY strong social pressures to use responsibly. I would go as far as saying that the negative social stigma of abusing drugs and alcohol have a much greater effect on their use than the actual laws written to prevent their misuse.

Similarly, I can imagine a world where live firearms training is not required by a state or federal law, but it is socially encouraged on such a strong level by those in the community, that more people seek training than don't. The argument to this would be to point out that not all gun owners run in the same crowd, as evidenced by the very strong social pressures to clean up and shoot in a safe manner at public shooting ranges, yet many of those places are trashed and considered unsafe by many shooters.