When I was a kid, I lived in a very bad part of Sacramento. I was about 11 when this happened.
It was me and my 3 brothers at home alone one day. Suddenly, a knock on the door.
"Package for you,"
Somehow I thought to look through the peephole instead of just opening the door.
No package. No uniform. Just a guy in plain clothes, and an unmarked windowless van on the curb.
I replied "you don't have a package!"
Suddenly the guy got angry and beat at the door. I jumped away from the door in fear.
"Open up, kid!"
One of my younger brothers said "let him in!" But I wasn't having it. I had never been more terrified in my life. I yelled, "I'm calling the police!"
I heard nothing on the other side.
After a few moments, I went back to the peephole, and he and the van was gone.
Told my parents what happened, and they found out the next day that a kid in the neighborhood was kidnapped. I never found out what happened to that kid, but I feel certain it would have been us if I had opened that door.