We have had a lot of homes recently burglarized in our neighborhood, and the police did an immediate "area check." Although the police didn't find this lurking human, they were very impressed with my "alert" skills. You see, a lot of dogs will loudly bark, which is good and scary. I do this during the day, especially when Evil Ones (aka cats) venture onto the property. However, when it's dark or someone is dressed in all black (especially if they are wearing hoods or hats), I do a "high pitched yap" and find a human for help. Crazy lady suspects I've had some training-- but, I'm not saying a word. I prefer to keep my allure mystique.
After all, it's just another day-in-the-life of a working dog!