The trick is that you are not really betting against the price, the true scalping (referring to forex in this example) requires you to use time frames of 1 minute, stay in front of your monitor constantly and be very very responsive to the price movements (in 1 minute you will see a lot of them) . You in fact need to just open and close hundred of transactions on a day , or thousands, or tens, it's depending on your strategy, buying low and selling high, but in a very fast way and taking every time a very small profit
Interesting site, looks well thought out.
I'm not sure I follow... if you are buying low and selling high, that won't necessarily work if the price is falling as the ask you place may not fill? I'm just trying to think of this in terms of trading bitcoin.