I personally really disagree with this idea. It encourages the same kind of popularity voting that takes place on reddit. If Unidan (before his fall) disagreed with something in a comment, the post he replied to would instantly be downvoted to a ridiculous degree, even on matters of opinion. There were/are many other users with the same influence, I just don't know them offhand. If users had limited amounts of negative votes to give, they would have to personally disagree, not just vote down on a whim because everyone else is doing it. I think that this in turn promotes more independent thinking.

As for the solution to your example, gladsdotter is on point, send a PM or report it somehow outside of the voting system.

Definitely, the fact that the site is gated with an invite req is awesome though since the people willing to seek one to make an account will probably be more active and interesting. Why go through the effort if all you care about is getting 2k upvotes with a meme/pun, you know?