Will Greene, an experienced promoter and producer of musical concerts, entered into a contract with Len Rencel, a rock singer, whereby Greene would promote several concerts for Rencel. Rencel belonged to the American Federation of Musicians (AFM), a union that represents most big-name musicians. The contract between Greene and Rencel was on a standard, preprinted form required to be used by all AFM members. The contract contained an arbitration clause that required any disputes regarding the contract to be heard and decided by the executive board of the AFM. When a monetary dispute arose between Greene and Rencel regarding the division of proceeds from the concerts, Greene sued Rencel in court. Rencel filed a motion to compel arbitration. Greene argued that the arbitration clause was unenforceable. Is Greene correct? Why or why not? What legal theory will Greene argue?