If policy distorts individual behavior and forces people to do things they would not do without the policy, then resources are reallocated. Unless society's goal is specifically to rearrange its resources, policies which distort are inefficient. The fairest policy. Economists are generally not concerned with subjective outcomes, like fairness. What is fair to one person may not be fair to another.
Economists have no real standards for measuring fairness, except through a social welfare function.
Unfortunately, what is fair for society may adversely affect certain individuals, who then think the policy is unfair. In fact, equitable outcomes are generally at odds with efficient or neutral outcomes and available only through a trade-off with efficient and neutral outcomes.