No, if they where hijacking it then it would appear automatically on any website that you click on in Google searches. That would be using it's force on the web. Google isn't gaining any content at ALL from this.
For the sidewiki comments to appear you have install the toolbar and THEN click on the blue arrow thingy on the left to make the side wiki appear.
Yeah I get it that you don't like not been able to control the comments about your site, but quite frankly tough. I don't like a lot of things from human greed to corrupt politicans to other people winning the lottery instead of me ;) Doesn't mean they are immoral or wrong.