Just as a different perspective: I have had several strangers walk right in my front door. I once came home to two strange men standing in the living room of my otherwise empty house. A few years back, I was making coffee in the kitchen when the scrufftiest looking hombre you've ever seen charged through my front door right at me with a pipe wrench in hand. Just this summer, my wife was on the couch watching late afternoon TV and a strange man walked right in on her.
Full disclosure: I live in a beach town, where people rent houses for a week or so and literally forget which one they rented. The pipe wrench guy was winterizing the home next door and absent-mindedly jumped in the wrong one.
Only once, I had some late teen boys creep in around midnight. We had just bought the place and I was working late there and crashing on the floor to save travel time. I guess they thought they were sneaking onto an empty worksite. I was sleeping upstairs, and grabbed the nearest weapon I could find (some kind of crowbar or something) and ran downstairs. They spit out timid and flustered apologies and beat a hasty retreat. It occurred to me a few minutes later that since I was working on the house in summer without the A/C working yet, I was sleeping bare ass naked and that's how I confronted the lads.