"Ignorance of the law is no excuse" is not a just principle when the laws are so numerous and incomprehensible that everyone is always ignorant of the law. Plenty of people just end up getting bad legal advice, even when they thought they were paying top dollar for a good quality law firm.
In some jurisdictions (I can only speak for Germany with some authority) if you've made a serious effort to get legal advice on a complicated topic and the legal advice was wrong this will (probably) mean that you're not guilty of a crime caused by the bad legal advice. Civil liability is a different topic obviously.
(But the "probably" is there for a reason: it really does depend on the specific topic at hand and whether you actually tried hard enough to comply with the law)
Is there some kind of good-faith test or controls to penalize bad legal advice? Because I could totally imagine some grey-area tax avoidance outfit partnering with some shady lawyer that will tell the client everything's legit in order to protect them.
