I was assuming that the desired course of action was to enter or exit a position, rather than to enter or exit a position with moderately high probability.
Generally, the HFT player provides "impatience service" - they give you immediate execution, and charge you a fee for it.
Unfortunately, since they invest in speed, they impose this service fee on everyone: When you join the bid or the offer, you are always behind the HFT player, and as a result you will only execute if there is a huge execution, or, (more probably) if the price moves against you.
This aspect of HFT is completely fair, btw - the HFT players are taking a risk, and they should be rewarded for it.
The part that is unfair is described very well by nanex in this thread - go read it.
