Fallen
I don't teach my children about stranger danger. It is a completely pointless exercise. Young children and even teens are not responsible for their own safety. Trying to make them responsible for their own safety is, IMO, wrong in the face of an evil adult who wishes to harm them.
I teach my children to say hello to adults we meet (cashiers in Tesco, bin men, police officers etc.). But they are all strangers, so teaching them not to trust strangers makes no logical sense.
What I do teach them is how to cross the road safely, how and why to stay in the same place if they get lost or separated from us and how to ask an adult for help.
I also teach them about good touching and bad touching. Since most sexual abuse takes place in a home environment with a family member.
I will in time teach them about pickpockets (we live in a capital city) and about gangs of robbers (we saw one such gang being arrested outside the restaurant where we had lunch today, quite harrowing actually.)
The chances of them being kidnapped by a "stranger" are so vanishingly small, I choose not to make an issue of it. I choose not to tell them that strangers are out to do them harm and I choose not to give them the idea that all adukts unknown to them are harmful.