Last year the Federal Court of New York was stormed by investors alleging that exchanges, banks, and broker dealers created an unfair marketplace through high frequency trading ("HFT").
The Court of Appeals in the 2nd Circuit held that a FINRA member firm and its customer may agree to settle disputes in court and not in FINRA arbitration.
If you invested money with Bernard Madoff, were a net investment "loser" with him in his Ponzi scheme, but had hope to claw back some of your losses from other Madoff victims who were net "winners," you just lost again.