Ds often says hello or waves to children he doesn't know at a park, for example. Almost always the other child responds by staring at ds as if he is nuts. I've also taught him to say "my name is shoppingbags' ds, what's your name?" as an introduction to play but again most kids ignore this.
So do your dc's respond to strange small boys or can you think of a better way he can introduce wanting to play with them?