According to Art. 152 of the Swiss Civil Procedure Code court shall consider illegally obtained evidence only if there is an overriding interest in finding the truth. At the same time according to Art. 184 of Switzerland’s Federal Code on Private International Law the arbitral tribunal shall itself conduct the taking of evidence. However, Swiss Civil Procedure Code is inapplicable to arbitral proceedings and the arbitrators have the power to rule on the admissibility of evidence.
It is a well-established practice that arbitral tribunals enjoy considerable discretion and are not necessarily barred from taking into account evidence, which may prove inadmissible in civil or criminal state courts. Taking into account CAS case law, CAS panels are likely to take into account evidence, unlawfully obtained, which would not be admissible in state courts of most of the countries. So far CAS has adopted an approach that the end justifies the means.