That and over zealous district attorneys are of great concern to some folks, especially those found guilty for crimes they didn't commit.
I have more trouble with the DA's than with the cops. I expect the cops to be the front-line troops who have to fight the war. I expect the DA's to exercise some judgement in what they prosecute and how they go about doing it. They know better. Supposed to.
But, like you say, that is not always how it works.