The most common reason. This occurs when a rider intentionally or recklessly makes contact with another rider at high speed, causing a crash that endangers a third party. The infamous 2018 Argentine GP incident with Marc Marquez—where he hit Valentino Rossi and then Aleix Espargaro in aggressive overtakes—directly inspired this rule. If a rider "uses" another rider as a brake or intentionally runs wide to force another off track, the Red Card follows.