A city wanting more residents to save for retirement adopted a simple policy: new employees were automatically enrolled in a savings plan unless they opted out. Enrollment soared from 40 percent under the old opt-in system to 90 percent under the new default. Officials declared the policy a triumph of 'nudging'—of steering people toward good decisions without forbidding any choice. A skeptical economist raised a harder question. Enrollment, she pointed out, is not the same as saving. Under automatic enrollment, employees are signed up at a low default contribution rate, and evidence from other cities suggests many never raise it, treating the default not as a floor but as a recommendation. Some of these newly enrolled workers, had they enrolled deliberately, might have chosen higher rates; the nudge may have captured them at a lower level than their own judgment would have set. Worse, a few may reduce other, less visible savings to offset the automatic deductions, leaving their total wealth unchanged. The economist did not deny that defaults move behavior—the enrollment numbers prove they do. Her point was narrower and sharper: a policy that succeeds at its stated metric may quietly fail at the goal that metric was chosen to represent.