[eru]

Your points taken together sound like a strange equilibrium from game theory.

In effect those hypothetical karma-hungry users amount to a voting ring, but one that does not need to communicate --- or even realize that they are in a voting-ring: Members just notice that sometimes --- when they are by chance the first to submit --- they get a huge karma boost. And when they are not the first, they do not lose anything from supporting the other members.

Potential solution: Decouple. I.e. do not make submitting an automatic upvote for existing stories. Just forward to the existing item and let people upvote (or not) manually.