Suppose you're Apple and you're thinking about suing Samsung on the claim they violate your patents. And suppose you think you're probably gonna loose, suppose your case isn't very strong. It looks as though it still pays to sue them. Because to begin with even if you're in the wrong you might win - there are mistakes in the court system, it's not a perfect system. And even if you loose, well - the case is going on, the people will be less willing to buy Samsung phones, because they are afraid that if you win, they'll have to withdraw some of their phones. That means you can sell more iPhones. So there's an incentive to attack people through the legal system, whether or not they're guilty.

David Friedman "Legal Systems Very Different from Our Own"