Here is one scenario based on an experience my "friend" had (not me--I am not "the friend.")
Traffic violations. Warrant out there, but never acted on. One day a knock at the door, informing the errant party that there is a warrant. There were no handcuffs, fingerprints, protecting the head as they usher them into the police car. Just, "get to the police station and pay the fine."
But in IL's friend's case, if a court appointment was required, I don't know what they would do. I don't think they would arrest him/her. And I really think chasing down warrants for minor things only happens when there's nothing else for the police to do or they have to up their revenue.
But it will catch up with them at some point--when they go to get their vehicle registered or something like that.