Individual race (mass start) at 5 km / 10 km / 25 km; Team relay: 4 swimmers (2M + 2W mixed) × 1.25 km each at World Championships; Officials: referee, course umpires (on motorized boats), feeding-station judge, timing officials
Why people argue about this
People often assume that yellow cards and red cards are only used for team relays in open water swimming events at World Championships, but actually, they apply equally to individual races as well. The confusion arises because this rule detail is not widely publicized or emphasized in the general rules handbook.
