As for "stranger danger" - the unexpected is always a possibiliity, I suppose, but strangers are so rare here that I stop and stare out of my kitchen door when someone I don't know walks past... happens a few times in the summer when we get tourists!
Here we do discuss the stranger danger issue in schools and parents get info to teach at safety programs etc...but parents are taught that most assaults are from people you know or who are established people in a commuity. The nice normal uncle, mentor, coach, grandpa figure type. More important is to teach about never going anywhere with with a grown up....not having any secrets with any grown ups, not going into anyone's car or house without mommy (or daddy) being with you, not even if they lost their puppy, have a bike for you, want to give you candy, etc. As they mature you can teach them about how most people are good but once in a while there is a person who is not nice and will try tricks like saying they will hurt mommy if you tell, etc. I would never say that at his age though, just to always tell mommy if any adult says to keep a secret. And no one touches or takes pictures of your or their private areas that a swim suit covers. It is a scary discussion but you can do it little by little. Q knows it and sometimes is afraid now to go to a public bathroom without someone standing close by which is actually fine with me.
We are also told to practice with them what to do if someone tries to take them somewhere, even if they seem nice, and mom does not know. Practice yelling the words "stranger danger" or "fire" or " this is not my mom, someone call the police" ...just screaming or saying help usually studies say people assume the child is just having a tantrum and stay out of it.
They also get permission to bite, kick, hit at ONLY those times.
I am sure it is hard when you live in a place where in order to be with other kids, and because it is the norm to do so, they are out of your sight. For us, in the city, we could easily leave our house but only be across the street at any one of several homes that were within the site of our parents. The parents hung out all day, with moms not working, so it was quite tight nit. YET, from the age of K through grade 2 my best friend's brother, son of my mom's best friend, at the home directly across the street from us, who took care of me often (sometimes for days like if a sibling was born)....would force me to hide under the pool table with him if we were playing games, he would make me touch him and he wanted to touch me but I finally made him stop. HE said OK but I had to continue to touch him and if I didn't he would tell my parents and I would have to go to bed at 7 every night and never get to play with all of them again. Sounds stupid but it was my biggest fear because everyone knew I had to go in the earliest of all the kids and how much I hated it.
In those days, and still I think in smaller close knit towns, people do not discuss, can't even admit this is going on and all evidence says it has always gone on and still goes on. We can only be aware and try to protect them as much as possible.