A hospital’s outpatient department needed painting. The area attracted heavy traffic during the day. So the painters’ supervisor and management agreed that for safety reasons, the painting should be done at night. Management changed the painters from their usual day shifts to night shifts. The painters’ union filed a grievance, claiming that management changed the painters’ shift to deprive them of overtime. The collective agreement barred management from changing employees’ shifts “for the sole purpose” of depriving them of overtime. Management argued that the shifts were changed for safety reasons, not solely to cheat the employees of overtime. The arbitrator agreed and dismissed the grievance [St. Joseph’s Health Care v. CUPE, Local 786,  CanLII 3100 (ON L.A.), Feb. 8, 2007].