I think everyone is right to be suspicious of payment for order flow, on the surface it does seem hard to get the incentives right.<p>That said, in your scenario (you were prevented from trading) how does <i>anyone</i> make money?  You were (probably) paying for a trade (which did not happen) and you were using infrastructure that costs money (placing orders), and no one was able to trade against you.  That is not a great business model...<p>Also, none of the groups we are talking about are banks.