Attacking the Customer: Coercing Patent Infringers While Avoiding Exposure to DJ Actions

To avoid declaratory judgment actions, patent holders may opt to sue or threaten the purchasers of an allegedly infringing product, without threatening suit against the manufacturer. In effect, the patent holder coerces the manufacturing company to give up the right to manufacture or distribute the accused product by scaring off its customers. The Federal Circuit frowns on this type of activity, but certain decisions have left loopholes patent holders may exploit. At what point does this activity create grounds for a declaratory judgment action by the manufacturer?