People don't buy locks so that they can lose their keys and require the lock to be picked. They buy locks to secure access to items or places. The parent I was replying to is saying that locks aren't security because a sledgehammer breaks them. I argue that a sledgehammer is only important for certain threat models. I am quite aware that most lock picking is for lost keys. However, I am describing threat models for which locks are important security. Do you understand?