I recently started reading The Gift of Fear and other Survival Signals That Protect Us From Violence. The author has been doing this a long time - analyzing these signals and providing data and support to the government as well as many people.
He starts out talking about an incident where a woman was carrying in all her bags in one trip and had her arms too full. One of the bags split as she was walking up four flights of stairs and her cat food cans went rolling down the stairs. A guy picked it up and said no problem he could bring it up to her. Her first instinct was "no, that is alright she could get it" as something sent a warning flare. First - she did not recognize the voice from being in her building and an alarm inside her head went off. But, he brought it up and was dressed nice and appeared to be a nice guy. So, she let him bring up her cat food but at the door she turned and said thank-you that she could take it from there. But, he insisted and that he would just help her by dropping them off and leave and they could even leave the door open. But, once she let him in he did not keep any of those promises and proceeded to torture and rape her for over 3 hours.
First - trust your intuition or your gut instinct. Whatever you want to call it does not really matter! What does matter is that you listen to that inner voice.
Second - more often than not the perpetrator is well dressed or at least nicely groomed and not what we typically think of. So, do not let this fool you and let down your guard.
We too often have a propensity to think that it will not happen to us but the statistics say otherwise. In the book he notes that in all of Japan the number of men killed by a gun in a year is equivalent to the number of men killed in a weekend in New York. Our armed robbery rate is 100 times higher than Japan's. Did you know that America's murder rate is 10 X's higher than other Western nations?
We can become part of the solution to not become one of the statistics!
Stay alert, prepared and pay attention to your instinct!