A spare key was supposed to make life easier, not turn someone’s apartment into a family free-for-all. After a brother trusted his sister with a key to check on his cat while he traveled, she gradually began letting herself in whenever it was convenient. Even after he asked her to stop, she kept coming over and eventually brought a friend along. When he finally changed the locks, the simple boundary dispute turned into a family argument. The full story of the siblings’ clash over privacy and trust is in the article.