It's a good opportunity to teach them. You could ask questions that lead them to the same conclusion (with the benefit of hindsight from your experience): "Wha

It's a good opportunity to teach them. You could ask questions that lead them to the same conclusion (with the benefit of hindsight from your experience): "What happens if this system is terminated before the final write call completes?" "How does this handle someone accidentally starting another instance of the application at the same time?" "If this external service we use is down, what happens?" You could also walk through the story of your prior mistake, draw parallels to the new code, and then discuss how to avoid it.