At work I think it has helped since we now have a clear procedure to follow if there's a problem.
Having the Code of Conduct be a public document rather than only an internal one means there are fewer excuses available for not following it — for example someone can't claim they thought it would be OK to ask a developer for sex since we wrote down that that's not OK.
It's also easier to explain in case the problem individual is employed by a paying customer.
