You might be thinking
too much about this and not seeing the forest, just the treees. A jury doesn't have to understand the nature of a case. If an ethical board finds against the actions of a professional, that can be used as evidence in the case and replace the need for true understanding. A jury will see that and it will become evidence for the case, simplifying the process greatly.
In the end, it is the threat of action and increase in potential menetary accountability that will pull everyone in line at the top, plus the threat of losing your license to practice will hold everyone in the middle.
Working in real estate, I've seen this up close and personal, it works for licensed Realtors (not Mortgage professionals, obviously). I would use the National Association of Realtors Code of Ethics as the framework for a financial code of ethics.
http://www.realtor.org/MemPolWeb.nsf/pages/COde
You could roll this into MBA programs, for instance, that way it reached those in positions who would require the license but not inhibit the multitide of lower level employees who are not in decision making positions.
In the end, could this have a negative impact on the industry? Maybe for a short while, but would be as negative as not addressing the myria ethical problems with finances? Well, I think the answer to that is in front of us now.