tedster - 7:16 pm on Jun 10, 2012 (gmt 0)
I think it's a good signal to send. On the article sites where I use this approach, I've noticed no confusion at Google. I don't see it as a guarantee, though - just one of many signals that belong together if you want the best results.
The key question I'd ask here is what kind of duplicate content issue are you seeing right now?