Abstract: The rules of many arbitration administrators (for example JAMS and FINRA) permit arbitral sanctioning by excluding evidence. There is a tension between these rules and Section 10(a)(3) of the Federal Arbitration Act. The Act provides for vacatur where “the arbitrators were guilty of misconduct in … refusing to hear evidence pertinent and material to the controversy…” Courts have drawn a line that arbitrators must respect. If excluding evidence prejudices the party against whom the sanction is imposed, the arbitrator is “guilty of misconduct” and any resulting award is likely to be vacated. The tension creates a dilemma for an arbitrator confronted with a disruptive behavior. Two recent decision by the same federal judge in the Southern District for New York suggest that prejudice trumps the desire of an arbitrator to rein in misbehavior. This article examines the two cases in depth and suggests that while well intended, the rulings unfortunately fail to consider the prejudice that misbehavior has on the other parties involved in the arbitral process. These two cases involved spoliation. The destruction of evidence can cause the inability of a party to prove a case, a result that is unquestionably absolute and prejudicial. The article suggests room for a rule allowing an arbitrator (and eventually a court) to weigh the respective rights of all parties when considering the impact of disruptive misbehavior of any kind. The judge’s rulings in both cases missed an opportunity to fashion such a rule.