Let's take one situation as an example. You're a woman experiencing domestic abuse in a mandatory arrest jurisdiction (means if the cops get called for a DV case, somebody is getting arrested). Your abuser also happens to be charismatic. You call the cops, your abuser cuts his own hand with the knife and convinces the cop that you were the aggressor, you're going to jail. Also, maybe you have trivial amounts of drugs in the house. Etc.

Google: "net widening effect"

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Hell, I'm white and middle class, but I used to look like a hooligan and the one time I called the cops (when someone I invited over to the house stole all of our laptops and a bunch of cash) I ended up spending the day locked in an interrogation room under suspicion for being an accomplice to the person that robbed me. (Somehow the cops became convinced that I arranged the robbery of myself to pay off a drug debt that I owed this person, because he was a known drug dealer and I invited him into my house)