An arbitrator who has worked well with both parties in earlier proceedings might be requested to formalize an already agreed upon grievance decision because political factors preclude a prearbitration agreement. Under the circumstances, the arbitrator may refuse to hear the case, may accept the case with the reservation of a decision on its merits, or may agree to hold a hearing to formalize the predetermined agreement. The issue of due process and fairness may be raised when a 'surprise' is introduced into the proceedings. A 'surprise' occurs when a witness, not produced in the grievance hearing, is introduced at the arbitration hearing. Options are to exclude the witness, let the witness appear in the interest of factfinding, or recommit the case to grievance proceedings. Another type of 'surprise' occurs when the arbitrator finds what may be a crucial relevant clause in the contract which neither of the parties has used to bolster its case. The central issue is the fairness of a decision on a principle not developed by either of the parties. Options are to reconvene the hearing and consider the relevant clause, solicit input on the relevancy of the clause to their case, or make a decision based on the clause without conferring with the parties. The author reviews the pros and cons of the various options proposed for each type of case posed.