As the National Institute for Labor Relations Research documents, every year there are hundreds of incidents of union violence, and countless more go unreported. However, since only a tiny percentage of them end up in arrests or convictions, people often have trouble grasping the scope of the problem.
This video (about a campaign of union violence and intimidation surrounding a strike in Westminster, VA) demonstrates how emotionally damaging such intimidation is to rank-and-file workers who refuse to toe the union line. The retaliation in this case took the form of Godfather-esque bullying. If only union violence was Hollywood fiction.