Question is, how do they investigate it? So if you are correct, they have a spider that "flag" suspected sites. Then they make a manual check. I saw in some post that Google had two people hired to do manual checks for the Swedish SERP. Interesting and good. As long as your site contains good content that is relevant to the keywords, my believe is that they will have a hard time penalizing your site even if its obvious that you also are getting unnatural links.
So, the old rule still applies (according to me), content and in-links is "king"

I've posted my own opinion in swedish about "Google SEO hysteria"
here.