What action should referees take when they observe illegal substitutions?

When referees observe illegal substitutions during a basketball game, their responsibility is to ensure the integrity of the game is maintained. This involves calling the game to a halt and correcting the substitution. This action helps to uphold the rules regarding player eligibility on the court, as illegal substitutions can give one team an unfair advantage or disrupt the fairness of the competition.

By stopping the game, referees can address the situation immediately, ensuring that the proper players are on the court and that the game resumes with the correct lineup. This intervention not only reinforces the importance of adhering to the rules but also serves to educate both teams about compliance, helping to prevent similar issues from arising in the future. This proactive approach maintains the flow of the game and ensures that all rules are executed correctly and fairly.