The Safety Net Effect: Is the Challenge System Making Volleyball Referees Complacent? When the International Volleyball Federation (FIVB) introduced the Video Challenge System (VCS), the goal was clear: eradicate game-altering errors, ensure fairness, and eliminate ugly court disputes over high-speed line calls and subtle block touches. By most objective metrics, the system has delivered accuracy. Yet, across major international leagues and top-tier tournaments, an unintended psychological side