It's not illegal to be a gang member. The US Constitution guarantees everyone the right to freedom of association and this association is the essence of gang membership. Gangs have their own distinct culture, adopt particular modes of dress, and use signs, symbols and code words to identify their members. This is also true of many other fraternal organizations but if being a Blood or a Crip was per se illegal, membership in the Rotary Club could also be banned. It's somewhat ironic that street gangs as social entities receive the same protections as any civic organization.
This is not to say that the Rotary Club is a subversive or criminal organization. On the contrary, clubs like these, work for the benefit of society as a whole. Urban street gangs, engaging in criminal activities do not. The operative phrase, of course is "engaging in criminal activities" so that an organization's focus and its members' activities can be suppressed by law enforcement. But first, the police need to have means of distinguishing gang bangers from Rotarians.
How do they do it?
Jimmy G hears through the grapevine that some detectives want to talk to him about a recent homicide. He knows he's not involved so he does the right thing and reports to the local precinct to see if he can be of assistance. When he gets there, several detectives from the Gang Investigation Unit sit down with Jimmy G in an interview room and read him the Miranda Warning. The detectives begin to ask the standard pedigree questions: "Full Name", "Address", "DOB", "SSN" which Jimmy politely answers. Nothing Jimmy says can get him into trouble until they get to the part about "Marks, Scars and Tattoos." Jimmy G has a number of tattoos.
Many law enforcement agencies use checklists to identify gang members. This is useful in a correctional setting because classification officers can identify members of "Security Threat Groups" to determine custody levels or to place gang members in separate housing units in a attempt to ward off potential conflicts. (For more information on gang classification in prisons, see:
A Jailhouse Lawyer’s Manual, Columbia Human Rights Law Review 8th Edition 2009 http://www3.law.columbia.edu/hrlr/JLM/Chapter_31.pdf )
Among the indicators police use to determine if someone is involved with a gang are:
Display of Colors (clothing including sneakers, hats, beads and bandanas)
Photographs of a Suspect Posing with Known Gang Members
Associating with Known Gang Members
Flashing Gang Signs (usually in photographs but also observed in surveillances)
Making Gang Related Graffiti
Voluntary Admission of Gang Affiliation
Gang Tattoos or Markings (scars or burns)
Any two of these indicators recorded by law enforcement can result in someone being identified as a known gang member. The individual will be associated with this label for as long as he or she has contact with the justice system. For the hard core gangster, this may be a plus but no for someone with only peripheral gang involvement.
The Constitution guarantees the right against self-incrimination in a custodial interview and a request to admit to having certain marks, scars or tattoos should not fall into this forbidden area of inquiry. However, in Jimmy G's case, the answer to this identification question can become an admission against his own interest and there is not much that either he or his lawyer can do about it. The consequences of this label can be quite substantial: Increased scrutiny of one's daily activities, exposure to enhanced penalties if charged with a gang related crime and more severe treatment by correctional authoities if convicted and sent to prison.