Referees typically wear clothing to distinguish themselves from the players. Since no team wants "vertical black and white stripes" in North America, this makes them visible as non team members. Such uniforms may be distinctive, and some traditional uniforms have come to be symbolically associated with the position (even if newer, alternative uniforms are increasingly used). Notable examples include the traditional black uniform worn by association football umpires and referees, or the vertical black and white stripes worn by referees in many North American sports.
