Dan was using his iPhone 5s and he got a message that someone is trying to sign into a device using his Apple ID. Apple says that they don't send out messages like that. Leo says that isn't really accurate as he's gotten those as well. Any time you sign into a new device, you get that message. If it comes with a suggestion to change the password, however, then that could be a ploy to steal his Apple ID from a browser. He should never do that.