These are your Weingarten Rights. They are federal law, and they were guaranteed in a Supreme Court case back in 1975. If you are ever summoned to a meeting with management that you feel can lead to disciplinary action against you, invoke your Weingarten Rights right away. Refuse to answer questions or continue the discussion until you are provided with union representation.
We have created a document to post on union bulletin boards in your work locations that provides members with language to use if they are ever called into what they believe is a disciplinary meeting with management. The file is 8" x 6". Print it out, and cut out around the border before posting (we get it that bulletin boards can get crowded, so we kept the document to half-page sized).
Find more information about your Weingarten Rights here.