The costs of appeal are assessed against the Plaintiff.

1. In the absence of the Supreme Court precedents on the interpretation of the statute applicable to a specific case in a small-sum case, where a number of small-sum case at issue of interpretation of the same statute is pending in the lower court, and there are cases where the Supreme Court has made a decision on what kind of case according to the full bench, on the ground that the small-sum case is a small-sum case, it would be likely to undermine the legal safety of people's lives if the Supreme Court terminates

Therefore, even if a small-sum case does not meet the requirement of “when a decision contrary to the precedents of the Supreme Court is made,” which can be considered as the grounds of appeal, in the absence of such special circumstances, determination of errors in interpreting and applying the substantive law ex officio at the level of performing the intrinsic function of the Supreme Court, which is unification

(2) The unjust enrichment system is a system that imposes a duty of return on a benefiting party based on the ideology of fairness and justice in a case where the benefiting party’s property gains lack legal causes. In a case where there is a change in a certain property value among certain parties, which seems to be justifiable in a general form. However, in a case where the change in property value among them is contrary to the ideology of fairness and justice, the return of value is ordered by ordering the acquisitor of property value to return the value, thereby resolving such inconsistency.

(see Supreme Court en banc Decision 2014Da5531, Jun. 25, 2015). Therefore, the issue of whether “legal cause” among the elements for establishing unjust enrichment belongs to the normative judgment area based on the principle of fairness, and thus, the nature of the act of payment is either the nature of the act of payment.