seo_marketing,
That is 100% false, the whole object is to get your article republished in as many places as you can, this builds inbound relevent links to your site.
You are worried about duplicate content, and that is not a factor with articles, if it were, the AP would be out of business online and there would be no squabble of rights to reprint AP articles on the web (they now charge for rights).
You may want to read this thread concerning articles and duplicate content.
Duplicate Content: It’s Not What You Think!
The bottom line is that the more it is published, the better off your site is, so it actualy gets better for you and your site if it is republished.
Jim