Travel Sentry, Inc. v. Troop

David Troop (plaintiff) held two patents for a method to improve luggage inspection using dual-access locks. The patented method involved a lock unlockable by the purchaser using a combination and unlockable by luggage-screening authorities, such as the Transportation Security Administration (TSA), using a master key. The method further involved an identifier that allowed screening authorities to identify the special locks and an agreement with screening authorities that they would look for that identifier and use a master key to unlock and relock relevant checked bags during inspection. Troop established and administered a lock system under the patented method. Travel Sentry, Inc. (Sentry) (defendant) began also administering a lock system that used locks with master keys to allow TSA to unlock and relock luggage. In 2003, Sentry entered an agreement under which Sentry agreed to provide TSA with master keys and screener training and TSA agreed to make a good-faith effort to disseminate those keys and use them to unlock and relock luggage during inspection. Troop sued Sentry for patent infringement. The district court granted summary judgment in Sentry’s favor, reasoning that Sentry had no control over whether TSA actually identified its locks and opened them using the master key, meaning that TSA’s actions in doing so were not attributable to Sentry. Without those acts being attributable to Sentry, the court found that Sentry had not infringed all steps of the patented method and was therefore not liable for direct infringement. Troop appealed.