AS integrity indicated it would be so easy for your competition to directly affect your sites in a negative way. Something Google clearly states is not possible …
Linking to all your competition with “www.site.com” and then with “site.com” maybe toss in a few “www.site.com/index.ext” and while doing so link to each from different sites. In other words trick google into believing those sites are duplicate content and thus have them “filtered out.”
I dont know many people that link to their pages/sites using httpx://www.mysite.com/page1.html and then turn around and link to it as httpx://mysite.com/page1.html … that would not only be sloppy but incompetent! If those links were originating from the same IP then and only then might Google filter one out.
If that were the case, I would surmise that the bots would be capable of determining which one to filter – assuming it was a unique coding mistake. If the entire site is in shambles – let the webmaster/site get filtered entirely – that’s what they deserve!
I don’t think the PR issues are related to “duplicate content” and moreover believe the redirects are NOT a necessity for the competent webmasters.