All kinds of laws have a "willfulness" requirement, which means that you had to do something on purpose. For things like vehicular manslaughter or public indecency, this means that you had to purposefully do something bad with your vehicle or expose yourself. Tragic vehicular and wardrobe malfunctions do not meet the willfulness requirement.

But the issue happens when you apply this standard to white collar crimes, because this makes knowledge of the law a legal requirement to being convicted of it. For example, let's consider the IRS own handbook[0] on tax crimes. This book explicitly includes wilfulness as an element for tax evasion on page 15. It defines wilfullness on page 17 as:

> Willfulness is defined as the "voluntary, intentional violation of a known legal duty."

It also helpfully notes (also on page 17)

> Willfulness is subjectively measured. A defendant's good faith belief that he is not violating the tax laws, no matter how objectively unreasonable that belief may be, is a defense in a tax prosecution.

So yes, if you're avoiding paying your taxes, ignorance of the law is a valid defense, and in fact the IRS agrees. This also applies to bank fraud, election rule fraud, etc. etc.

0 - https://www.irs.gov/pub/irs-utl/tax_crimes_handbook.pdf