This is already happening. Some bloggers like ryanwaggoner are openly asking for upvotes by submissions at the end of the blog posts. So, unfortunately, this is something that will always remain broken.

I think that an active HN member "asking for the sale" at the end of a post is clever and responsible marketing.

More so than many blogs' gratuitously inflammatory titles or even having widgets to submit every post to Reddit or Digg or every other site under the sun.

Then you build a system that detects voting rings and other irregularities like too many votes from a certain geographic location without that geographic location being mentioned in the title (protects Hacker News Nights)