Quote from Jerkstore:
The question could be it's own thread. I would love to hear from the IB rep on this one. I don't know the exact regulatory obligations and limitations, so take this with a grain of salt...
BUT, when you choose "SMART" on your routing, the broker will do everything he can to use your order and order information to make money-- either through fee arbitrage or by finding a way to "internalize" your order (though technically internalization doesn't happen in options, i am using the word for lack of a better one).