In Season 3 Episode 15 of Avatar: The Last Airbender, Sokka was put in line when the Prison Warden found out that there is an impostor among the guards. All guards were asked to come out and Sokka was out too. Chit Sang, a prison inmate, was asked to point at the impostor and he pointed at another guard.
Sokka would have been caught outright because he was tying his hair using a blue band which is a colour of the water nation people and all other guards present tied their hair with a red band.
Why was he not caught because of this?