When you look at typical charts you notice that much (and often, most) of the close-to-close price change occurs in the opening gap. So, is anybody successful at night trading? I.e., entering a position at the close of a day and exiting the next morning shortly after the open. It looks tricky -- the gaps seem to go in either direction pretty much at random.
I think with enough backtesting, and narrowing down your parameters you could formulate a solid overnight strategy, but like any other trading strategy if you just try to guess you won't be successful.