So 50% is the arbitrary cutoff then? Anyone that gives 50% or more of their votes to the same people is an "abuser". Hmm I actually see a lot of accounts that fall into your arbitrary definition on here.

By the way, people forming groups and mostly interacting in those groups is normal human behavior. That's pretty much what a community is. Expecting people to scour the site and vote for 10 or more 'quality' (whatever that means) posts each day, mind you by 10 different authors so we aren't voting the same authors on consecutive days, isn't.