On Sterling Software, which is leased to a few prop firms, and on other systems like SLK's Redi+, you can set up a purchase hotkey like: "Ask+.01" or "Bid+.01". If you carefully watch the B/A spread you'll see those fraction of a cent price improvements used to jump in front of a speading freight train. Nothing special with that scenario, just a means of scalping. Take this concept one step removed, and realize that in order to achieve the initial scenario (that started this thread) there would have to be 1 MM to set the pick and others to already be positioned to advantage the setup, whilest the original MM changes, cancels his "shot calling" B/A, and then begins to trade in the "projected" direction. Simply put, this is not the parlance of just one trader within a shop, or just 2 traders in 2 shops, its the parlance of a few traders within one shop, and the same at the other shops. Collusion or not, there's evidently something to this story, or its just fantasy.