So, do you have an example of an implementation that doesn't have this problem or are you just assuming one exists? If there is one, it must be a well kept secret, because there hasn't yet been a social news site that's adopted it.

One I've considered is to temporarily suspend down voting after submitting a story. But this has some unintended consequences in that it unfairly penalizes the people who submit heavily, who provide a lot of value to the site.

Your assumption that people ordinarily upvote submissions they like isn't necessarily valid. I usually read the site pretty passively, and only upvote things I think are really spectacular. It doesn't mean I don't like the other things I read, just that they didn't really blow me away.

"counter to the idea of upvoting" is a pretty vague phrase. Counter to your idea maybe, my criteria for upvoting fits my idea of upvoting just fine. Not everyone thinks of a vote the same way, as another story on the front page right now points out, this is one of the problems with a site like this.