The trend of authority is strongly in favor of eliminating the aggressor defense from Workmen's Compensation law. The instigator, like the victim or participant in horseplay, is now likely to be compensated for his injuries resulting from sportive acts. This is looked on by the law as a reasonable consequence of the natural conditions of employment rather than as a deviation. "Horseplay" is the colloquial term referring to sportive and playful acts often used legalistically to describe the conduct of employees who skylark or prank, doing injury to themselves or to others. Sportive conduct includes assaults with or without an instrumentality furnished by the employer, during actual working hours or in periods of enforced idleness, before or after the close of the working day.
Michael Kaye, Horseplay by Employees, 15 Clev.-Marshall L. Rev. 104 (1966)