Unions are one of the most democratic institutions that I know of. They often have regular membership meetings with financial disclosure available at any time. This exceeds the norm, for instance, for small business or the business community. I think being accountable has been a principle of the unions since they were established. They are a members organization and believe in being open and accountable. I think that the system works well.
On March 21st, 2016. See this statement in context.