[He's actually wondered the same thing, especially given just how many different worlds there seem to be out there. It's never not unsettling, so he chews the inside of his cheek before he answers.]

For me, I think of it like this: If this is the kind of place where anyone from any world can be "recovered" and made to stay, why wouldn't there be people that know about us? It's almost one of most normal things about being here.