As does purchased order flow, internal matching, preferred routing agreements, dark pools etc.
But given the simplistic nature of the discussion it is more accurate to say that in general HFT don't see your order before it hits the market than it is to say they do.
Okay, as long as people who actually want to understand the issue know that in many cases HFT firms can actually see orders before they become public although they don't actually do much to disadvantage a retail trader.
But given the simplistic nature of the discussion it is more accurate to say that in general HFT don't see your order before it hits the market than it is to say they do.