 In addition to the private sector surveillance industry, governments form another traditional group that uses surveillance techniques at a large scale, either by intelligence services or law enforcement. These types of surveillance systems are typically justified with an appeal to the “greater good” and protecting citizens, but their use is also controversial. For such systems, one would typically like to ensure that any negative effects on privacy are proportional to the benefits achieved by the technology. Especially since these systems are typically shrouded in secrecy, it is difficult for outsiders to see if such systems are used proportionally, or indeed useful for their tasks (Lawner 2002). This is particularly pressing when governments use private sector data or services for surveillance purposes. 