Can an employer unilaterally alter its representation by practice conduct to its detriment?

101. A practice may or may not constitute a representation or part of a representation by conduct. The mere existence of even a lengthy a practice may not by itself be sufficient to establish the basis for an estoppel. It is only when the employer has consistently applied the collective agreement in a way which is patently inconsistent with the words of the applicable provision(s), and the union has relied on that practice by not seeking to have the wording of the collective bargaining provision changed to reflect the actual practice in the workplace, that the employer may be estopped from unilaterally altering its practice in that respect without giving the union notice of its intention and an opportunity to address the matter in collective bargaining. The onus is on the union to establish that it in fact relied on the employer’s representation by practice conduct to its detriment. Regardless of the length of a practice, the mere fact that the employer has chosen to exercise a management right in a particular way, or to apply a collective agreement provision in a way which is not patently inconsistent with the collective agreement, will not by itself freeze that practice or constitute a representation that the employer will not alter that practice. In order to engage the doctrine of estoppel in such circumstances there must also be a sufficiently clear and specific representation that the employer will not alter the practice, either in reliance on its strict legal rights under the collective agreement or otherwise, in circumstances where the union actually had and forsook an opportunity to bargain the matter in reliance on that representation. (See, for example Columbia Forest Products v. United Steelworkers, Local 1-2995,supra, in which I concluded that a 30-year practice did not in the circumstances by itself constitute a representation by conduct sufficient to ground an estoppel.)