Paul,
have you considered personalising as a method of minimising trolling?
As you pointed out, people do things on forums that they wouldn't do in person. IMO, this is partly because they're hiding behind a handle and partly because their target is.
I'm not sure how you'd go about making accounts have more personality and identity, but IMO that would be considerably more effective than just instructing people to behave like they're face-to-face. They know they're not.
As a hill-climbing algorithm, wouldn't this approach tend to result in the local optimum rather than the most general truths?