> I'm usually all for paranoia when it comes to the police but knowing your identity based on your appearance isn't really a violation of your rights. It would

> I'm usually all for paranoia when it comes to the police but knowing your identity based on your appearance isn't really a violation of your rights. It would be one thing if there was some RainMan FBI agent who was the database and could recollect the name, address, declared weight, height, eye color and hair color of half of the population of the United States after meeting them through natural social introductions. But this is a collection of databases that hundreds or thousands of cops can search through simultaneously without having to know anything about the unidentified person. Recently, it was declared unconstitutional to attach a GPS tracking device to a vehicle without a warrant, yet it's still perfectly acceptable to have a real live person tail another individual in another car without a warrant. The reasons being is that a small police force of say 20 people could in effect virtually tail and track thousands (if their budget allowed them to purchase that many devices) of individuals at once, where physically tracking those individuals is a natural limitation of the capacity of the force. It enforces a burden on the police. Exactly the same rules apply here. If a cop knows a subset of individuals in his or her neighborhood, and then comes across a picture of unidentified person taken during the commission of a crime, and is able to identify that person from memory and develop further proof that the individual in the photo was in fact the one that committed the crime, then they have a good case. If the only way for the cops to identify that person is to look up the identification of the suspect via a highly sophisticated computer algorithm that can check against hundreds of faces per second, then the "capacity" of the force to identify suspects far outweighs the effort the public had to counteract that. Checks and balances, and all that stuff, don't just apply to the 3 branches, they apply between the citizenry and the powers over them too.