Where one's misreliance upon a supposed duty is the result of two mistakes, one of fact and one of law, he is not entitled to relief in jurisdictions where money paid under mistake of law cannot be recovered:

Needles v. Burk, 1884, 81 Mo. 569; 51 Am. Rep. 251: Action to recover the value of certain property delivered to the defendant in satisfaction of a supposed liability for the alleged act of the plaintiff's infant son in negligently setting fire to the defendant's barn. Hough, C. J. (p. 572): "It is settled in this state that a father is not responsible for injuries inflicted through the negligence or willful wrong of his minor child. The plaintiff, therefore, was not liable to the defendant, Burk, for the value of his barn, even though it had been set on fire by the plaintiff's son. If the plaintiff's son had fired the barn, and in consequence thereof, but in ignorance of the fact that he was not legally liable therefor, the plaintiff had paid the defendant the amount of his loss, it would not be pretended that he could recover it back."

1 Bank of Chillicothe v. Dodge, 1850, 8 Barb. (N. Y. Sup. Ct.) 233, (mistake by Ohio bank as to the New York statute governing issue of commercial paper). See Norton v. Marden, 1838, 15 Me. 45; 32 Am. Dee. 132; .Etna Ins. Co. v. Mayor, 1896, 7 App. Div. 145; 40 N. Y. Supp. 120,124, (mistake by non-resident as to legality of New York tax assessment).

Professor Keener suggests that a plaintiff who seeks to recover money paid under a mistake as to the law of the jurisdiction where the action is brought would not be allowed to recover if, though a resident of another jurisdiction, he paid the money in the jurisdiction as to the law of which he was mistaken. "Surely," he says ("Quasi-Contracts," p 94), "a court would not be justified in saying that a non-resident is entitled to relief, though making a mistake as to the law of the jurisdiction where the money was paid, while in that jurisdiction, when a resident making a similar mistake would have no right to recover." But on the other hand, would a court be justified in saying that since the residents of a particular state are presumed to know the law of that state a foreigner who happens to be in the state temporarily must also be presumed to know its law ?

If, however, the misreliance upon a supposed duty is the result of a mistake of fact alone, the circumstance that the plaintiff also labored under a mistake of law which affected the policy of performing the supposed duty should not prevent a recovery (see ante, Sec. 18). For example, if by the law of Missouri, a father were responsible in damages for the torts of his minor child, and the plaintiff in the foregoing case had paid under a mistake as to the fact of the commission of the tort and also under a mistaken belief that he was criminally responsible for his son's act, he would have been entitled to a recovery. For the only mistake as to his legal duty to pay would have been a mistake of fact; the mistake of law would have affected merely the policy of making the payment.