We are often asked about how to train children and teens to have their own defense mechanisms for danger -- whether its to resist predators, avoid porn or other risky behaviors. A parents alert system for danger is vastly more developed than a child's. It's a function of the higher reasoning centers of the brain which are unfinished until young adulthood (about 25). Simply telling a child "porn is bad for you" or "never talk to strangers, and certainly never meet up with someone you don't know" is not going to develop the alarm system they need when Mom or Dad isn't there.
For a neural network to be created and then reinforced enough that it will survive the pruning process that happens in adolescence, it requires Repetition AND Reward. Think of it as stages of working out: you want to target an area to strengthen/flatten so you do specific exercises. The first time feels awkward and unpleasant, but if you get the endorphin release you can be motivated to continue. Learning safe habits is very similar.
Let's say you want to help your child understand people with bad intent can act very politely, even friendly. So begin with practice situations, such as, learning a safe word. In the beginning, use it like the game "Mother May I?" or "Simon Says" -- games where you can only advance a step if you say that specific phrase. Let them pick the word, then use it whenever they ask to go somewhere or do something. "Can I go watch TV?" then you ask "What's the safe word?"
Always make a big positive deal if they get it. Remind, don't reprimand. You want the interplay to produce a positive dopamine reward, which turns on the mechanism to make a neural connection. Don't nag -- if they forget the safe word, tell them what it is, and then say, "Ask me again," and follow through with praise.
When they have the hang of the idea of a safe word, the second stage is arranging practice. Tell them "Sometime soon we are going to test our safe word system." Explain that someone they know is going to suggest he/she go along with them. But you really want your child to verify of that person knows the safe word. Get a relative or a neighbor to offer to take them to the park (somewhere fun), and if your child asks for and receives the safe word, then make a huge positive deal of it.
Just remember, "practice" can't be a one-time thing. Think ahead for any situation that you can, such as, any time they are picked up or dropped off anywhere. Always with a huge positive response for asking and getting the safe word. Repetition makes the connections stronger.
Obviously, the safe word may need to change a few times while you're practicing, but if you practice getting the safe word frequently when they are small, it will be a habit by the time they're teens. An extra word of advice, if you are starting a safe word habit with a teenager, also encourage them to choose a "safe emoji" as a text signal that means, "I want out of this situation. Call and say you need to pick me up."
The time and effort it takes to learn to do this as a family will pay off. The parents in this video clearly thought they had taught their children about dangerous and risky behavior, but found out the hard way their children didn't quite get the message.