As a non-american this is ridiculous, and I want more details. What crimes do they cover? Just traffic? Or can I going shoplifting? Or settle a score with someone?
It covers whatever the police agree to look the other way for.
As someone who has one, only minor traffic violations. And only in certain places (cops not in the northeast generally are not unionized and dont honor them. ) It's not a get out of jail free card like it's being described.