There was a period several years ago when I went to Mars Hill with my sister (it didn't last all that long, and once I realized how bad it was I stopped going and got her to stop too, thankfully).
One week though, towards the end of one of his sermons, he going on one of his women bashing rants about how ladies need to dress more modestly to get respected by men, and to illustrate his point to gave an analogy that I immediately recognized as a Dave Chappelle stand-up routine.
He basically ripped this bit off word for word, aside from the very beginning part about titties popping out of the turtleneck: http://www.youtube.com/watch?v=J7QNw1LRJ…
He just substituted his name for Dave Chappelle in the bit. I was looking around in awe, like "a room full of people and none of you have seen that stand-up special before!?"
So no, if that guy would blatantly steal material from Dave Chappelle, I'm not surprised he'd rip off authors too.