If the person one party has called as an expert doesn't know what they are talking about, that's a wonderful opportunity for the other side to discredit them. If your expert doesn't know what they are talking about, you should not use their testimony (see above). If nobody in the world knows whether a witness or expert knows what they are talking about or not, that's functionally equivalent to them being right, and there is nothing anybody can do about it.

I don't understand how it could be considered just for someone to be punished for making an honest mistake in their testimony.

> Seems the rich and powerful get given carte blanche to lie and ignore any predictable consequences of their decisions.

They aren't[1]. This doesn't seem to be a case of someone rich and powerful getting away with lying.

[1] They may have the means to fight things in court to reduce their penalty for perjury, but that's not "carte blanche". Rich and powerful people do, in fact, get penalized for lying under oath. Just not 100% of the time.

>I don't understand how it could be considered just for someone to be punished for making an honest mistake in their testimony.

His job is to run the company and take responsibility for it. If he doesn't know something illegal is going on, he is still at fault for not learning about it

This flirts with the is/ought fallacy. The way you wrote, it sounds like you’re saying that in our current legal system they can be found “found at fault” in a legal sense.

But I believe what you meant is that under a different/hypothetical legal system, one which you believe to be closer to optimal, they should be found at fault.