The chances of your order being bucketed in this day and age are pretty slim. Computerized audit trails and sequential trading cards have in the last ten years made it much easier for the exchange to figure out whether an order was in a brokers hand before or after he traded at that price for his own account. In fact at the CME "dual trading" is banned altogether. Since the FBI sting in '89 here in Chicago, where 40 some guys were booted off the floor for life, and a few actually did time in club fed (some for pretty innocuous stuff) the message has gotten through loud and clear.