It is delusional to imagine that front running never occurs. It would be a simple matter for some criminal to develop influence over a broker through various methods, and there would be no obvious tie between broker and the other guy, who would then have access to selected order information a second or two before the original order is placed. Remember, most of us imagine a world without guile, where one is never deceived or tricked. There are others who imagine how to bleed the system like a financial parasite. Not saying it happens a lot, but you better believe if I can conceive of it, some organized crime figure already thought of it decades ago. Would an honest broker not being extorted or blackmailed, routinely engage in this practice? Of course not. The risks are too great for the price he would pay if caught. Not much temptation there. Is it common for a broker or brokerage contractor or employee to fall under the control of a ruthless and dishonest person? No, not common. The scheme is probably more trouble than it is worth, TBH, and if it was widespread, it would be in the news and on prosecutorial agendas. There are better ways to milk that cow, I am sure. But there undeniably are career criminals who specialize in persuading honest people to do dishonest deeds. I am thinking when you do stuff like that for a living, you get pretty good at it, too.