The Street Terrorism Prevention Act makes associating in public or private with another gang member grounds for suspicion of criminal intent.

Federal agents use the broad powers of anti-gang ordinances to detain youths they suspect may be immigrants with gang affiliations, Los Angeles, US. Copyright © Donna De Cesare.
More than half the states in the US have adopted street terrorism enforcement and prevention laws. Two brothers can be charged with criminal conspiracy for appearing on the street together if they belong to the same gang.
Links:
- UN document on racial prejudice in application of US gang ordinances.
- Gang prevention: OJJDP National Youth Gang Symposium
- Gang prevention: The National Gang Center
- Article from ColorLines: The War on Youth