What is recommended for substitutes while warming up outside the team area?

Using distinguishing pinnies for substitutes during warm-ups outside the team area is recommended because it aids in identification and ensures that substitutes can be easily recognized by both officials and other players. This is crucial during games, as it helps to prevent any confusion regarding which players belong to which team, especially when multiple teams are warming up in close proximity.

Wearing regular uniforms could cause confusion, as it may be difficult to distinguish between players and substitutes, particularly if there are other teams nearby. Matching socks or hats can also help with identification, but they are not as effective as wearing pinnies, which are specifically designed to stand out and differentiate players. By using pinnies, substitutes are clearly marked, promoting safety and organization during the warm-up period.