Per unit of BP, there is less risk. However, just because you are long or short a spread doesn't mean you don't have directional risk. You have risk of the spread diverging, or converging, and a spread can diverge or converge as much as an individual security can go up or down. It's riskier to trade pairs without an edge than to trade a single security with an edge.
While at the NY Trading Expo I saw two representatives from Think of Swim excuting their pairs trading strategy. The guy who was doing the trading is Tom Sosnoff. If you are serious about pursuing this type of trading you should contact them so that you can begin to get a sound education in how to execute the technique successfully. *** Not an endoresement, just sharing info. Good luck to you.
NO. If you look at a chart of a spread and remove the symbol, it looks like a typical stock chart. Non-directional means you are not relying on general market direction, but the pair can certainly move up or down and trend like any stock.