Consider the alternative way this "strategy" can go:

- Put in a standing order to sell a small amount slightly below market.

- Wait until you receive a "TRADE CONFIRMATION 100@$10" message.

- Buy a lot of same security very fast and put in a sell order at higher price.

- No one actually buys it.

- Loss

This is actually a very risky strategy and very few people do it.

What's actually happening most of the time is a far less risky one:

- Put in standing order SELL 100@$10, 100@$10.05, 100@$10.10

- When you receive TRADE CONFIRMAtiON @ $10, cancel other orders and reprice higher (maybe $10.20 and $10.30).

- Maybe put prices back if you don't get filled in an hour.

The goal here is to offer a good price $10.00 to Joe Sixpack (no delta toxicity), but to offer a worse price to Bill Ackman (high delta toxicity).

How? You can't because your competition is already resting orders there (from potentially weeks ago) and any order you put in there will be behind your competitors no matter how fast you are.

What does happen is that you all are resting orders up and down the order book. When a big order takes out several levels of your orders, you race as fast as possible to cancel those same levels at other exchanges. If you are faster than the big order you only get hit for a single exchange.

Its a risk mitigation technique, to keep your profits from your regular business of making the spread, not risk free profit.

So one place firms are racing is on the cancel side. The other is on filling back in orders after the big order has cleared levels. The faster you are there the better priority your resting orders will have (potentially weeks from now).