I’ve often said the same things you said; that it’s usually not strangers we have to worry about. I know from personal experience. For years, I was inappropriately touched by my grandmother’s boyfriend ( The Paedophile We Loved, my story on Medium). He was grooming me from the beginning. I was his favorite. He bought gifts for me, but not the other three grandchildren.
In another, unrelated, earlier incident, a twenty year old man exposed himself, grabbed me, and tried to get me to touch him, but I got away. I was six years old. My father knew his father. Instinctively, I knew what he tried to do was evil. I felt sick to my stomach. Somehow, I also thought my father would kill him if I told. I told no one. When I was in my late teens, I found out the man went to prison for sex crimes. I still didn’t tell. I finally told my sister when we were in our late thirties.
You’re so right. Children must know what is not normal touching, not to keep secrets, and that they can safely tell someone.