International Arbitration and International Commercial Law: Synergy Convergence and Evolution

One may say that the iura novit curia2 principle (or the judge knows the law) only comes into play when bad lawyers present bad arguments that lack a full and comprehensive analysis of the applicable law and its contents. Yet, this principle has found its way into various decisions not all of which resulted from bad lawyering. But has it become a universal principle that is generally applicable in International Commercial Arbitration or is it just a rare occurrence that differs in application and scope depending on the circumstances? Are tribunals bound by the parties' legal reasoning or can they apply a different legal basis ex officio without exceeding their mandate? How should tribunals ascertain the applicable law and its contents anyway if left in the dark by the parties? Should tribunals allow for a "sneak-preview" of their legal thinking and permit the parties to be heard if it departs from the parties' legal reasoning?