It seems like this "second price auction" would be a wonderful thing to try in a tribe or SMT. Come to think of it, vote negation could also just be applied to a tribe or SMT as well.

Agreed. With an SMT or tribe that's tied to a token with actual value, you'd also get a realistic view of human behavior when the technology is available. In a case of ironic timing, I just left this comment on a steemitblog post, shortly before you posted this article yesterday.

Curious: aside from choosing different author/reward ratio splits on SMTs, might it also be possible to experiment with different rewards distribution algorithms? Specifically, as I have long advocated, I think that something like a Second price auction, combined with a super-linear curve to penalize stake-splitting would go a long way towards minimizing both upvote & downvote abuse, and I'd love to see an SMT run the experiment.