I'm gonna venture that nothing insidious is taking place here for two reasons.
1. HFTs compete fairly vigorously to take all the queue positions that contain alpha.
2. As someone noted earlier, especially in ES, there's a tendency for guys to jump in with some size behind you as soon as you enter the queue and then cancel when enough flow for them to get hit appears imminent.
This isn't undergrad subject matter, but I would guess that this is done to induce you to believe the queue behind you is sufficient to give you a high enough expectation of getting filled on the order side after your order gets hit by an aggressor but before the queue behind you runs out. They cancel and go market to take on your order, leaving them with your position, the illusion of strong order flow, and what you would assume to be pretty good queue position on the opposite side at the next price level, therefore they have a pretty good shot at capturing the spread if enough people replace on the fresh bid or offer.
Just one explanation though. Others may know better. You would have to be pretty fast to pull this off.
1. HFTs compete fairly vigorously to take all the queue positions that contain alpha.
2. As someone noted earlier, especially in ES, there's a tendency for guys to jump in with some size behind you as soon as you enter the queue and then cancel when enough flow for them to get hit appears imminent.
This isn't undergrad subject matter, but I would guess that this is done to induce you to believe the queue behind you is sufficient to give you a high enough expectation of getting filled on the order side after your order gets hit by an aggressor but before the queue behind you runs out. They cancel and go market to take on your order, leaving them with your position, the illusion of strong order flow, and what you would assume to be pretty good queue position on the opposite side at the next price level, therefore they have a pretty good shot at capturing the spread if enough people replace on the fresh bid or offer.
Just one explanation though. Others may know better. You would have to be pretty fast to pull this off.