Spike the vote - cheat digg

As sites get popular and potentially change the way people start looking at Internet - you get these "cheat" sites which claim to help you utilize the cheat. Be it Adsense ,Ebay or now Digg. Spike the Vote creates a community and diggs each other's stories so that they get it on the front page

Spike the Vote works on a point system. Each day I give you a mission with several stories to Digg. 20% of your mission involves digging stories submitted by users in this community, while 80% of of your mission is completely random. This is to eliminate footprints and keep things anonymous.

You earn 1 point for each story Dugg. Once you earn enough points, you can trade them in for Diggs on your own stories.

I wonder if all these really work and Digg would come up with a way to prevent/blacklist such methods.