In case of a player wearing a cast, who has the final authority on its safety?

The umpire in charge of the game has the final authority on the safety of a player wearing a cast. This is because umpires are responsible for enforcing the rules and ensuring a safe playing environment during the game. They have the necessary training and understanding of the rules related to safety equipment, including casts, and are tasked with making decisions that protect all players on the field.

The other individuals mentioned, such as the player's coach, opposing team's coach, or the player's parents, may have their own opinions or concerns about the safety of the player with the cast, but ultimately, it is the responsibility of the umpire to assess the situation objectively and enforce the rules appropriately. This centralized authority helps maintain fairness and safety throughout the game.