DS is 4 and has just started school. I'm aware that this is a more vulnerable stage than when he used to be with me or at nursery, where they give anyone they don't recognise the 3rd degree at pick up time. I also don't want to specify 'stranger' - more 'don't go with anyone that I haven't told you to go with'.
But- is his the right age and how do I start the dialogue without frightening him?