How authentic do we have to be?

Mick Porter asks how our preaching is affected as certain behaviors become more culturally acceptable:

To clarify a bit with an example - picture yourself preaching on James 1:27 - "Religion that is pure and undefiled before God, the Father, is this: to visit orphans and widows in their affliction, and to keep oneself unstained from the world." So, where would you be comfortable to go in applying this? Would you be happy to exhort people not to watch TV, or would that be a problem because (a) you watch lots of TV, or (b) it's too counter-cultural (or perhaps (c) that you don't see this as a valid application). So how about preaching on submission of wives, leadership by husbands, servanthood of leaders . . .

I like the way John Piper went and adopted a child, so that he could speak out on the abortion issue and back it up with his own life. I wonder how much we really constrain our sermons by our own examples and not wanting to preach hypocritically. And how much we constrain them by not wanting to rock the cultural boat.

Good questions.