Mandatory meetings, imposed by management, in which workers are subjected to anti-union messaging have long been allowed and used as a weapon against unionization by companies. The National Labor Relations Board general counsel, Jennifer Abruzzo, believes this practice occurs only because of a misunderstanding of labor relations law and plans to encourage lawmakers to explicitly make these "captive audience" meetings unlawful.
In a detailed article on the practice and the NLRB's efforts to combat it, Reuters author Hassan Kanu quotes Professor Matthew Finkin about how this practice might be coercive.
Read the full article at Reuters.