Yes, it is possible for Shop Stewards to be disciplined.

Becoming involved with the Union does not mean that you cease to be an employee. In your role as an employee, you face the same set of expectations that any other employee faces - performance appraisals, compliance with work rules, etc. 

You do have a degree of representative immunity meaning that you cannot be disciplined for ‘vigorously advocating’ on behalf of your co-workers when engaged in your role as a steward.

So remember to always be clear with the employer when you are acting in your role as a Shop Steward. Be mindful of your interactions when acting on behalf of the Union, and remain professional and respectful.

If you think you are facing unfair treatment because of your union activity, talk to your Chief Shop Steward and Local Executive members to develop an effective and quick response.