> I thought HN wasn't doing that for a week
We weren't, but since a week turned out to be longer than needed and I was worried about the cost of continuing, we ended the experiment early: https://news.ycombinator.com/item?id=13131251. So it's back to the normal guidelines now.
(The worry about continuing was because there was evidence that some people thought the change was permanent, and that was not the intention.)