I've written before about how idiotic I find cop "expert" opinions frequently are. I basically feel that these are political positions masquerading as some kind of strong science. Police and prosecutors put up these silly opinions all the time to "educate" the jury about certain crimes. As the crimes have become more plentiful, and as the level of activity that will allow you to be considered violating that crime increases, and as the number of silly enhancements have increased, so have the number of times in which police officer "opinion" testimony comes in.
Let me give you a little hint - police officer opinion testimony is always that the person charged is guilty - their opinion as to some area of their "expertise" will always conform with that opinion, always, no matter what the circumstances.
Someone has a single joint - could be possessed for sale. The police saw him smoking it? Still could be possessed for sale. He said he wasn't selling? Drug dealers frequently lie, he still could be possessing for sale. They didn't see him do anything consistent with selling? Drug dealers are cagey people, he still could be possessing it for sale, and therefore, the officer still has that opinion, and the jury hears a "respected" member of law enforcement give them the opinion as to the ultimate issue in that case, whether it was possessed for sale, that is almost impossible to disprove (how do you disprove a negative?).
But in the area of gangs it has become even more absurd. Proposition 21, the "Juvenile Justice" bill (put in quotes here because much of the law it changed had nothing to do with juvenile law), made any crime committed for the purpose of a gang a strike. Paint your nickname on a wall, not only did it just turn into a felony (as long as someone can say it costs $400 to paint over), but it is also a strike. Pick up any new petty theft the future and you may get 25 to life (if you painted 2 walls, that is, and got 2 strikes). It gets even worse, though. When giving their testimony about gangs, police are able to bring in any unfavorable character evidence against the defendant that they want, and not just against the defendant, but also against any of his friends, family, acquaintances, etc (they may all be in the gang, after all).
So now, just about any innocuous offense can be alleged to be committed "for the benefit of the gang," no matter how non-gang related it really is. Have a gun? Possessed for the gang. Have some drugs? Possessed for the gang. Write a bad check? Did it for the gang. Slap your wife? Did it for the gang. Rob a bank? Did it for the gang.
And now, no matter how weak a case is against any particular defendant, even if the person is really innocent, the jury will hear all of this terrible character evidence - much of it not even related to the particular defendant but to his acquaintances, that will prejudice them against him even further, working to prevent him from getting a fair trial on the particular facts of the case.
And worse of all, the DA now won't dismiss these idiotic gang allegations once filed. So, even if you have someone who is guilty of possessing that gun, or having a couple of joints, or writing that bad check, or scratching their name into the bus bench, they must now plead to a strike to resolve their case or go to trial and face the mountain of bad character evidence that will be introduced against them, all ensuring that no jury will ever give them a fair shot.
This is the daily level of idiocy from police and prosecutors we have to deal with. I'm not saying my clients are angels, believe you me. But, they deserve a fair shot in life without having a pre-paved highway to life in prison being set out before them by the time they're 18 years old. Give these people a shot, because, believe me, if you don't give people a shot, they will be far more likely to take one at you.