But they're doing it voluntarily. optional 4-day week with lower pay for the employees that want it = ok employer-enforced 4-day week with pay equivalent to c

But they're doing it voluntarily. optional 4-day week with lower pay for the employees that want it = ok employer-enforced 4-day week with pay equivalent to current 5-day week = ok employer-enforced 4-day week with lower pay = not ok