Not just that the CEO or board "knew" because that is a hard thing to prove. Better to have it be "reasonably should have known". If this is a thing that the company is doing and has been doing for a long time then the senior managers should know about it and are therefore liable and responsible. Such a rule would also incentivize managers from 'looking the other way' at wrong-doing because the saying 'I didn't know' won't matter.