I wonder how many people gave kudos to the post by mistake? I know I did and there's no way to remove the kudos you gave afterwards. User actions should be a click not a hover.
He's already received complaints and sort of laughed them away: http://dcurt.is/unkudo Personally I think it's bad UX, but what do I know; I'm not Dustin Curtis.
If you don't think this is a big deal, I invite you to think about a natural extension of this concept: A comment form that sends its entire contents to the server on every keypress.