What is the test for admitting or denying a grievor's evidence at a grievance arbitration?

17. Strictly construed, Browne v. Dunn posits that even actually relevant evidence must be excluded if admitting it would offend the fundamental principle of fairness, and a party that has not acted fairly cannot be heard to complain when evidence that it considers important is excluded as a result of its own conduct. However, if there is any doubt about admissibility it is generally appropriate for a grievance arbitrator to admit arguably relevant evidence which would otherwise be excluded by operation of the rule in Browne v. Dunn, particularly when the evidence in issue is that of a grievor whose employment has been terminated.

18. It has been suggested that it is appropriate and even a “practice” to permit the party that wishes to call the evidence objected to subject to the right of the other party to call reply evidence in that respect (see, for example, Machado v. Berlet et al. (1986) 57 D.L.R. (2d) 207). I agree that is appropriate if it is judged sufficient to ameliorate the unfairness inherent in not bringing the impeaching or contradicting evidence to the attention of the witness and the party calling that witness. This is notwithstanding that reply evidence window appropriately a small one, and that permitting or a party to call reply evidence in a true Browne v. Dunn situation may lengthen the hearing.