Knowledge of the act, not knowledge of the law. There are very few contexts in which you can be punished for not knowing an illegal act took place, and they are all situations where you should have known but were negligent.
negligence casts a very wide remit, but applies mostly to professionals (ie, credentialed staff). general executives are granted considerable leeway with respect to negligence in many context it would appear through things like the 'business judgement rule', where bein incompetent is a legitimate excuse and not presumtive negligence. INAL but just throwing this out there for discussion to see some other sides of the issue.
Knowledge of the act, not knowledge of the law. There are very few contexts in which you can be punished for not knowing an illegal act took place, and they are all situations where you should have known but were negligent.