The quote they are using has been attributed to James Whitcomb Riley, who sometime around 1883-1885, said: "When I see a bird that walks like a duck and swims like a duck and quacks like a duck, I call that bird a duck."
According to the National Gang Center (as of December 2011), among the often-used criteria for identifying gang members is that they are:
- identified as a criminal gang member by a parent or guardian
- identified as a criminal gang member by a documented reliable informant
P59: Testimonial statements of witnesses absent from trial have been admitted only where the declarant is unavailable, and only where the defendant has had a prior opportunity to cross-examine.
P68: Where nontestimonial hearsay is at issue, it is wholly consistent with the Framers' design to afford the States flexibility in their development of hearsay law — as does Roberts, and as would an approach that exempted such statements from Confrontation Clause scrutiny altogether. Where testimonial evidence is at issue, however, the Sixth Amendment demands what the common law required: unavailability and a prior opportunity for cross-examination.
P69: Where testimonial statements are at issue, the only indicium of reliability sufficient to satisfy constitutional demands is the one the Constitution actually prescribes: confrontation.
I suspect that due process should be a consideration when classifying a gang member either on the streets or in jail/prison, so a hearing would be the logical followup to such classification if it were to be challenged. It's not a huge reach to suggest that the statement/testimony of another (non police) person should be subject to challenging by the accused gang member.
It could also be a problem for those jurisdictions that use the points system to confirm gang members (summarized in Stuff gang bangers in the military can't do with DoD Instruction 1325.6 in place):
1. Self Admission
3. Hand Signs/Symbols/Logos
4. Wearing of Gang/STG colors, gang clothing, gang paraphernalia.
5. Possession of Gang/STG documents
6. Possession of commercial Gang/STG publications.
7. Participation in commercial Gang/STG publications.
8. Consistently in contact with Gang/STG members
9. Contact with Gang/STG members.
10. Participating in a photo with Gang/STG members.
11. Outside jurisdiction documents.
12. Correspondence with Gang/STG members.
13. Named a Gang/STG member in correspondence.
14. Confirmation through outside agency gang unit or database.
15. Engaged in Gang/STG Crime or activity.
Numbers 13, 15, and 16 require the statement of another, non-law enforcement/corrections person to be used against the gang member in order to confirm them. That's similar to hearsay, which is allowed only in a select few, specific circumstances. Specifically, in Crawford v. Washington, 541 U.S. 36 (2004). I suspect that 17 would be fine, as the credibility of informants is measured based on a track record so they would likely be closer to police than an everyday citizen.
It may not be a problem for those using civil law to counter the gang problem . . .