The Supreme Court makes its biggest headlines when it wades into the biggest issues of the day. But the Supreme Court also maintains a substantial docket of seemingly small—but ultimately important—technical questions.

In recent years, the Court has been particularly interested in defining precisely when an hourly employee is on and off the clock. For example, earlier this term, the Court held in Sandifer v. United States Steel Corp. that employers need not compensate certain workers for time spent donning and doffing safety gear. The Court will answer a related question next term. Yesterday, the Court granted certiorari to decide whether end-of-shift security screenings to prevent theft are compensable time under the Fair Labor Standards Act, as amended by the Portal-to-Portal Act.

Although such screenings may take only a matter of minutes, when aggregated over the course of a two-year limitations period for numerous employees, the damages exposure can be substantial. That explains why a series of nationwide back-pay class actions have been filed in the wake of the Ninth Circuit’s decision that time spent in security screenings must be compensated.

The Supreme Court will now review that decision in Integrity Staffing Solutions, Inc. v. Busk, No. 13-433. The legal issue is whether security screenings are “integral and indispensable” to employees’ “principal activities” or merely “preliminary” or “postliminary” to those activities. Under the Ninth Circuit’s view, security screenings are compensable because the task is necessary to the employees’ work and done for the benefit of the employer. But the Second Circuit has described security procedures as “modern paradigms of the preliminary and postliminary activities described in the Portal-to-Portal Act.”

Integrity Staffing is likely to be among the first cases heard when the Court reconvenes after its summer recess. Until then, expect the wave of related class actions to continue.