3 suing HSBC for forex losses

Three foreign investors are suing HSBC for losses in trading forex. They claimed that the banks did not allow them to use certain trading strategies which resulted in the loss. This is a case of clients wanting to use their own strategies but not allowed to. What about cases where stock exchanges allowed unfair strategies or trading practices eg computer trading, cornering the market, short selling, etc to make profits against small investors? Would there be a day when investors will stand up to sue stock exchanges for allowing unfair trading practices to go on at their disadvantage? Is there a moral and legal ground for stock exchanges to ensure that trading practices are fair and equal to all parties? I know that cornering a stock is illegal. To what extent is a situation that makes a stock being cornered? Is a stock cornered when a few parties work in collusion to drive up or down its price and incurring losses to the innocent, ignorant small investors? There must be moral responsibility, justice and fair play in all stock exchanges to ensure that all parties have a fair chance to trade, to win and to lose in the market.