I believe the repricing behavior you describe is far more common now than the more aggressive strategy. Several years ago, before the exchanges got rid of "flas

I believe the repricing behavior you describe is far more common now than the more aggressive strategy. Several years ago, before the exchanges got rid of "flash" orders, a variation of the more aggressive strategy was common, but under limited circumstances. The way it worked was that after a limit order was partially filled on exchange A, it would show the remaining size at the limit price very briefly before routing it to the other exchanges (this was the "flash"). If the limit price was a few ticks through the other exchanges best prices, the HFT's would take those prices out and offer at the order's limit price. Less risky because they knew the order would be automatically executed at that price as long as there was an offer there.