Beware forcing bosses into nonexempt work.

Retail, restaurant and other frontline managers who are classified as exempt often have to step in and perform non-managerial work when needed. Normally, that doesn't destroy their exempt status. But if an employer purposely minimizes the number of hourly workers assigned to shifts, the risk of managers losing their exempt status rises dramatically.

Recent case: Eric, a manager at a Red Robin restaurant, filed a Fair Labor Standards Act suit and brought in 500 other managers he believed were being improperly classified as exempt.

Eric said Red Robin's "lean staffing" model meant exempt managers had to spend most of their day performing nonexempt tasks like...