Can you prove this contention? Since you made the assertion, I'm sure that you'll be able to cite sources that prove your assertion, right?
scour the police scanners, the newspapers and local news for SWAT deployment. Gang bangers aren't hard to find. Most of the upper level or OGs have parole officers and have to check in. Now how hard is it to figure out who is holding the drugs, whonis holding the money , who is running the girls and who is a foot soldier and has possession of weapons. Fail a drug screen and you are off parole. Associating with known felons- parole violated, in possesion of a firearm - parole violated. But not many of those case's have seen the light of the courts.