The Google webspam team seems to prefer psychology over technology to solve the problem, especially recently. Nearly everything that's come out of Matt Cutt's mouth in the last 18 months or so has been a scare tactic.
IMO all this does is further encourage the development of "churn and burn" websites from blackhats who have being penalized in their business plan. So why should I risk all the time and effort it takes to generate quality web content when it could all come crashing down because an imperfect and overzealous algorithm thinks it's spam? Or worse, some intern or non-google employee doing a manual review wrongly decides the site violates webmaster guidelines?