Quote from trickshot:
Yes thats true, this is why I have always believed that its not possible to daytrade and make money in very efficient markets (which will inevitably be infested with bots/HFTs/etc). However this does not mean that every market/instrument is efficient, there will always be loopholes and opportunities, I arb'ed the crap out of such a "loophole" for over 4 years before too many market participants found out about it, but I already made a bundle from it so I am moving on to look for other opportunities in other markets/instruments.
Imo betting on direction for any instrument intraday is suicide, no egde will compensate any trader for taking intraday directional risk because the market is random (and more so in the very short run!), the odds of any trader winning is much less than 50% after accounting for trading cost.
This post sounds more believable about intra day trading in random markets.

