"Robustness" and Regulating Vice

I have not yet read Prof. Leitzel's paper, referred to in Rob's post, but it is hard to see how the robustness principle could be limited.  Once one says that state action is justified based on the fact that actors make less than rational choices, that opens a broad sphere in which the state can act to protect one from the personal harms caused by one's irrational choices.    Based on irrational choice and level of harm, one can argue that there is more justification for the government to regulate everyone's calorie content and diet than some of the vices Leitzel mentions.  I'd also be worried about whose idea of "their own good" is being promoted.  I'd be interested in hearing ideas for how the principle (which I agree with Rob is intriguing from the standpoing of promoting human flourishing) could be framed in a way that limits it.