A person who claims to be in a gang but is not an offical member. The only thing that makes them a member is the fact that no one else around him/her knows the truth.
Guy1: Wut up folks?
Guy2: Shit nigga(shakes up and walks off)
Guy3: (to Guy1)Dont do that shit again. He aint folks he a false flagger.
A person on a communication website (Facebook, Twitter, etc;) who unwillingly flags something for no reason. The website that has had the most false flagging is YouTube which sparked the Flagger's War. It is also rumored people do false flagging because they are jealous of the user or hate them. They flag (or report as inappropriate) a user or a video (etc;) until the account is frozen. But it will (or might) get their account frozen.
Girl: Wow...this person's video sucks...I am going to flag it.
Girl's Friend: Whoa! I didn't know you are a False Flagger!