Stewards are afforded special status when they engage in their official union role under what is commonly referred to as the equality principle.
In short, stewards obtain equal status to management when acting in an official union capacity. That means that conduct that might be considered grounds for discipline — insubordination for instance — must be tolerated by management when an employee is performing in their role as a steward. Adversarial and spirited exchanges of views and/or debates can be part of the process when a steward communicates with management. While granting a steward the status of an equal opposing party to management, the equality principle does not mean that a steward can do whatever he/she wants, namely engaging in insulting, threatening or abusive behaviors. If management inappropriately disciplines a steward acting in an official capacity, they can be sanctioned for engaging in an unfair labor practice.
Closely related to the equality principle is the equal standards principle, which prohibits holding stewards to higher standards than other employees since they “should know better” than others.