If someone unintentionally breaks the rules, do they break the rules? In the abstract, the answer is obviously "yes." But, surprisingly, when considering specific examples of unintentional, blameless rule-breaking, approximately half of people judge that no rule was broken. This effect, known as excuse validation, has previously been observed in American adults. Outstanding questions concern what causes excuse validation, and whether it is peculiar to American moral psychology or cross-culturally robust. The present paper studies the phenomenon cross-culturally, focusing on Korean and American adults, and proposes a new explanation of why people engage in excuse validation, in terms of competing forces in human norm-psychology. The principal findings are that Americans and Koreans engaged in excuse validation at similar levels, and older adults were more likely to engage in excuse validation. OPEN RESEARCH BADGES: This article has been awarded Open Materials and Open Data badges. All materials and data are publicly accessible via the Open Science Framework at https://osf.io/8juyc/. Learn more about the Open Practices badges from the Center for Open Science: https://osf.io/tvyxz/wiki .