flashing colors
The situation when someone is accidentally or intentionally exposing (showing) colors from their clothing that relate to a gang 'color' causing alarm or suspicion from anyone that notices, especially authorities such as the police.
Young individual walking in the mall wearing all blue: hey why the hell are you questioning and searching me as if I'm carrying any weapons?! What is this the gestapo, I thought this was a free country, I could wear whatever the hell I want!
Two undercover cops: well there's been a gang stabbing here earlier and you were 'flashing colors' (wearing all blue).
Two undercover cops: well there's been a gang stabbing here earlier and you were 'flashing colors' (wearing all blue).