There should be a counter, or something that alerts the user how much self-voting they've done during the current pay period that warns them, the more they do it.. So they can visually see when they are beginning to overdo it.

Example: I've self-voted this comment of mine, because I believe my suggestion is important and don't want it hidden way down at the bottom. But if you look at my blog, under my comments section, you'll see I don't upvote the majority of my comments. I save that ability for when I have something important to contribute.

BTW.. Good post, and good suggestion. We need more suggestions to fix this problem before it gets worse.