Wouldn't be the first time a website operator did that (I've seen the Atlanta Urinal-Constipation do it).
I've also seen someone add thousands of votes to the liberal positions on his poll to offset a FReep. He later claimed that he had to do it to put the numbers back in perspective.
Yet somehow the Der Spiegel doesn't see fit to discuss this in the realm of online polls. It must have been edited out along with their interview with Jim Rob (certainly they must have tried to contact him for his perspective) along with the accounts of other websites/blogs that have posters encouraging someone to participate in an online poll.
Bill Frist's staff ran an online poll on his government website. It was getting DUped hard (I think it may have been over same sex marriage but it could have been some other liberal HOT issue).
The operator's solution was to rotate out the question (sometimes with a similarly posed question but with reversed "Yes/No" perspective). In the end there was a last minute swap for an earlier poll that had already been FReeped (too late for them to DUpe).
Such a shell game at least kept those Rats from DUping other online polls for a couple of hours.
There is a running account of it here: We're Gettig CREAMED! Vote in the Frist Poll OFTEN!!!!! Calling ALL FREEPERS!