This presentation reports findings from a study examining how Japanese university EFL students use AI tools for academic tasks, how they interpret ethical boundaries, and how emotional and cultural factors shape decision-making. Data from survey responses and open reflections reveal that students want guidance rather than prohibition and view AI as a supportive tool rather than a replacement for learning. The findings highlight both successes and failures in classroom integration, ranging from increased confidence and clarity to academic dishonesty cases and AI misunderstanding of student needs. The presentation connects these classroom realities to broader questions of responsible AI use in CALL and considers what it means to “prevail or fail” when integrating emerging technology into language education.