From the opinion of the court, "If the test could be satisfied merely by the fact that an employer required an activity, it would sweep into 'principal activiti

From the opinion of the court, "If the test could be satisfied merely by the fact that an employer required an activity, it would sweep into 'principal activities' the very activities that the Portal-to-Portal Act was designed to address". The Portal-to-Portal Act was in response to miners suing for back pay the time they spent moving between mines (after Congress enacted laws that made that seem like a winnable case). It was understood and customary that the time was to be unpaid (thus presumably their wages already took that into account). The relevant portions of the Portal-to-Portal Act (as quoted by the court) are: (a) Except as provided in subsection (b) [which covers work compensable by contract or custom], no employer shall be subject to any liability or punishment under the Fair Labor Standards Act of 1938, as amended, ... on account of the failure of such employer ... to pay an employee overtime compensation, for or on account of any of the following activities of such employee engaged in on or after the date of the enactment of this Act— (1) walking, riding, or traveling to and from the actual place of performance of the principal activity or activities which such employee is employed to perform, and (2) activities which are preliminary to or postliminary to said principal activity or activities, “which occur either prior to the time on any particular workday at which such employee commences, or subsequent to the time on any particular workday at which he ceases, such principal activity or activities. So there's an exception for activities which are customarily paid. I am not sure why the court worried that paying these temp workers would go against what the Act was designed to address. Most people would expect a required security screening like this one would be customarily paid time, thus is has to be paid under the law.