Even before that, you need two things that can't be taught at seminars: street smarts and social skills. I've only ever been caught up in violent/potentially violent encounters out of choice to defend other people or because I didn't want to put up with antisocial behaviour. Before I'd done any training I would be the guy that the nutters would want to buy a pint and tell their life story to. More than once I thought a punch in the face would be preferable. Avoidance always seemed obvious to me, and thinking on my feet to talk my way out (usually talk my friends out) of a situation with someone spoiling for a fight came naturally. The use of interpersonal skills depend not only on the defender, but the aggressor as well, and how the two interact in at any time, in a particular context. There are so many variables that I'm not sure you could really codify it, and teaching that to the people who need it most would be a life's work.