For example (see below): What you make on Ang Lee, you lose to Steven Speilberg and vice versa. BUT the profit for those playing them both long is still 3 points. That means the rest are 'safe' profits for another 8 ish points. 11 points on a hedge bet is better than a 5 point 'short everything' strategy.
The risk certainly exists if there is a complete upset in the category. Then you would lose both your longs and the short that was picked. could be up to 53 points in the negative in this case.
Choose your risk, choose your strategy, choose your reward.