They should at least be barred from being board members for a certain period of time.
Why, if they did nothing wrong and had no knowledge of anything illegal?
It is extremely rare to see that kind of prosecution in western countries (US or EU).
Because they should have known. They should have made it their business to know. Looking the other way on purpose should not be a valid legal defense.
> Looking the other way on purpose
Hell even if not on purpose. The point of a board is oversight. If management can commit illegal acts without the board's knowledge, the board has failed. Of course incompetence in a board role shouldn't lead to prison. But it should at least bar someone from future board jobs for a few years.
Pour encourager les autres. If there's illegality going on at a company and the board doesn't know about it, future boards will make sure they are better informed.