Facebook is continuously checking the fake accounts. When you try to log in your Facebook account and you will see a notification your Facebook account has been disabled. If you use Facebook in such a way that doesn't follow the standard guidelines/terms and conditions, then your Facebook account may be disabled. Using a wrong identity, impersonating someone, sending spam messages, and harassing other users are all examples, that why your Facebook account is disabled. If you save your Facebook account being disabled then follow the terms and condition at https://www.facebook.com/terms.