Now I am sure, pretty sure anyway, that is not exactly what they said. But I reject the entire premise - the whole culture of fear/everyone is out to get you/trust no one! So we launched into re-education mode, a frequent occurrence around here.
There he is surrounded by strangers! Run! Scream!
Me: Eion, what am I to anyone who doesn't know me?
E: A stranger.
Me: Right. Do children need to run from me?
E: Maybe sometimes I do.
Me: But other children?
Me: Lots of strangers are normal people, just like me. It is ok if people, even strangers, talk to you.
E: What if they are bad?
Me: Then you run and scream. If someone tries to take you or touch you in a bad way or get you to do something wrong, you know they are bad and you leave.
E: Good, because I like to talk to people.
Stranger danger. You know what is the real danger? That my kid is being taught by his school that he is surrounded by potential murderers. We're not going to conform on this one.