"Jesus is here calling into being a community of voluntary commitment, willing for the sake of its calling to take upon it the hostility of the given society."
I think Yoder's onto something in linking voluntary commitment to following Jesus and the ability of a community to take upon it the cost of discipleship, and I'd extend it to the individuals-in-community. Apart from saying 'I believe in this, count me in,' can we really live this way of life, given the impingements on our level of comfort, both from within our communities and from the broader society which can be both hostile and indifferent to the way of the Christ?
I've got in mind the phenomenon of nominal Christianity, and the common reaction against a perceived-to-be repressive religiousity which often rears its head in the teen years and early twenties. I think this is linked to the imposition/expectations of certain standards and commitments, not necessarily bad ones, but nonsensical apart from a larger rubric. For the scholarly minded, I've got Sanders' term 'covenantal nomism' in mind here. The way-of-life of a follower of Jesus doesn't make sense on its own (granted, what i think about as the standards are very different from those of much of American christianity, as evidenced by the unwritten expectations of 'Christians' and the codes of conduct at Christian colleges). When compared to other societal norms, it makes even less sense, so we reject it, often with a great deal of hostile emotions. As for the consequences and implications, young folks don't necessarily see these, and I don't think this is necessarily their fault. In order to see a reality larger than ourselves, we often need people to point them out.
Summary of this rabbit-trail: Faith can be incubated, but i'm not sure that it is inherited, and a lot of the 'rebellion' issues that arise in youth groups and Christian colleges are linked to this phenomenon. Yoder stresses that Christian commitment is voluntary, and we'd do well to heed his words and wait and see if someone's in a faith-community by their own volition, rather than in response to a perceived expectation, before holding them accountable to our communal norms.