I swear to god, I witness this every day while trying to trade oil futures. I watch institutional orders for as many as 200 contracts (almost $1,000,000 worth of margin) appear just below support or just above resistance, and as soon as a large market order goes through that will push through that order, the order is instantly retracted, faster than my trading platform can even perceive. These orders exist for less than 1-3 seconds, typically, and they make me so angry. These people aren't happy robbing new investors by using investor wisdom (perfectly legit). They have to do it in a snaky way like this. It makes day trading (which is a perfectly valid thing to do - it provides liquidity to markets, and offloads near-term risk to those willing to take it for a small profit) impossible for anyone with less than millions of dollars and close-to-market connectivity (e.g., large cables leading to a server room next door to CME or NYSE or NASDAQ, etc.) to have a chance at surviving.