Arbitration - class actions
Neither the terms of the contract nor the incorporation of the arbitration organization's rules constituted a clear and unmistakable consent to allowing the arbitrator to define the scope of a class arbitration.
http://www2.ca3.uscourts.gov/opinarch/151275p.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.