In that case, it could be in the group's interest to end the ethical problem to which the public has knowledge, but keep remaining breaches hidden.
Another exception would occur in industry sectors with varied membership, such as international brands together with small and medium size companies where the brand owners would have an interest to protect the joint sector reputation by issuing together self-regulation so as to avoid smaller companies with less resources causing damage out of ignorance.
Similarly, the reliability of a professional group such as lawyers and journalists could make ethical rules work satisfactorily as a self-regulation if they were a pre-condition for adherence of new members.
The results can be disastrous, such as a military with no external, independent oversight, which may commit human rights violations against the public.
The House Ethics Committee is an example in the United States government, while various police departments employ an Internal Affairs division to perform a similar function.