An unfair list, also known as a strike list or a do not work order, is a term describing a list, compiled by trade unions, of employers who are known by members to have engaged in unfair or strike-worthy labor practices, including:
Typically, for purposes of solidarity, union members are prohibited by union bylaws from engaging in a contract for the rendering of services to entities which are listed on the unfair list.
References
Unfair list Wikipedia(Text) CC BY-SA