Coercive power is government’s most frightening weapon (one that libertarian paternalists fear as much as libertarians), and the conventional wisdom inside and outside of academia says that bureaucracies that use this power to implement and enforce a given regulation will be more successful than those that do not.
Ironically, when looking at the data, there are a number of cases where coercion is not necessary for a successful policy (though no universal rules about when these cases occur).
Nudge blog 