29 U.S.C. § 106 — Responsibility of officers and members of associations or their organizations for unlawful acts of individual officers, members, and agents

This section protects individual officers and members of a labor union or organization, and the organization itself, from being blamed in court for someone else's illegal actions.

If a labor dispute happens, no officer or member of an association or organization, and no association or organization taking part in or interested in that dispute, can be held legally responsible or liable in a court of the United States for the unlawful acts of an individual officer, member, or agent of that group.

There's one exception. A court can only hold them responsible with clear proof that they actually took part in the unlawful act, actually authorized it beforehand, or found out about it afterward and ratified it (approved it after the fact). Without that clear proof, the officer, member, or organization is not liable.