> it might not be in the best interest to downvote someone
  > into oblivion on one of their first posts to Hacker News

I disagree. If someone doesn't have the courtesy to try and understand the community they are participating in before they participate, lowering an arbitrary number associated with their username is hardly any kind of punishment. The only impact it has on the user is that they now have to earn back points on their arbitrary number. If it also bans them from posting for a while, even better.