this phenominon (did I spell that right?) exists in nature, hence in the markets, and in human conduct....
observe the ocean swells before/after a storm, what happens to the tide level?
observe the effect of soda, milk, orange juice, martini(s) in a glass when a vacuum relocates the volume of liquids (straw being used)...
observe the effect of the small traders gathering at a post because they know the reputation of a large trader entering the CME pits on the level/rung that the large traders stand on....
a) all the small and medium sized locals and commercials trade in front so as to:
a1) directly profit from being where the action is....
a2) profitably accumulate a position large enough to sell into the anticipated change in demand due to the re-appearance of the large trader
a3) earn a riskless profit from instantaneous buy/selling or selling/buying into the anticipated demand due to the re-appearance of the large trader
what you're fussing about is how efficient markets actually work....
the trick is to position yourself to profit from being there