Basically instead of giving them a sense of control, it's to give them actual control. What I promise to do is release a new version of whatever they want at least once a week, and hopefully more often. If every week (or every day) they get to decide what that is, they stop caring about estimates. More here: https://news.ycombinator.com/item?id=21071374

And I also wrote something up in response to a previous HN discussion: http://williampietri.com/writing/2014/simple-planning-for-st...