Some tax forms ask information that seems to have no effect on the bottom line. No matter how you answer the question, your tax bill is the same either way. In Europe, this sort of thing would violate the data minimization principle of the GDPR. So the question is, what happens to people who either leave the intrusive fields blank, or they give bogus info? I’ve heard that tax penalties are generally a constant × the amount of underpayment. If underpayment is zero then so is the penalty, correct?