i do have kids and i make it a point to get to know other parents of my kids friends. they are not strangers. a stranger is someone who i meet once and never see again, or don't meet at all. parents of my kids friends or even any parents from my kids school are not that.
what bothers me here is that on the one hand we have this concept of stranger-danger, and on the other everyone is a stranger, just because you haven't talked to them yet? that doesn't make sense. calling the parents of my kids friends strangers just feels very wrong to me.