deadsea - 3:58 pm on Apr 1, 2012 (gmt 0)
Based on Google's initial blog post:
If you decide to update your page layout, the page layout algorithm will automatically reflect the changes as we re-crawl and process enough pages from your site to assess the changes.
Given that folks aren't recovering the possibilities are:
1) It doesn't work like Google intended and they need to re-run something on their end, or they have a bug
2) Many of us that were hit were actually hit by something else on that same day.