My book club in Austin banned spoilers after one meltdown

We had this monthly meetup at a coffee shop on South Congress, and last March someone casually dropped the ending of The Silent Patient before we even ordered. The person who hadn't finished it threw her bookmark across the table and walked out for ten minutes. That moment changed how we run every discussion now. We started doing a quick check-in at the start where everyone says what chapter they're on, and if someone's behind, we agree to only talk about themes and character vibes, not plot twists. The rule is simple: spoilers get you assigned the next meeting's snack duty. Has anyone else had to create a spoiler policy for their group after a similar blowup?