During a match, what action should a referee take if the libero is out of position during lineup checks?

When the libero is out of position during lineup checks, the correct course of action is to assess a penalty against the team. This is implemented to maintain the integrity of the game and adherence to the rules regarding player positions. In volleyball, the libero has specific restrictions and roles, including being designated in a specific position on the court. If the libero is not correctly identified in the lineup or is out of position during a check, it indicates a violation of the rules surrounding player positioning.

Calling a penalty in this situation serves as a corrective measure to promote compliance with the regulations that govern how teams must organize their players, particularly with a specialized role like the libero. This ensures that teams are held accountable for misalignments during lineup checks and helps maintain fair play.

In contrast, allowing a substitute or accepting the lineup disregards the rule violations and could compromise the game's fairness. Halting the game could be an appropriate response in situations where immediate correction or clarification is needed, but it does not directly address the violation of the libero's positioning. Hence, assessing a penalty emphasizes the importance of correct lineup practices and player roles in the sport.