And the reality is such cameras are designed to be pointed at public spaces. So what if the cops can see it? Using technology to expose that which is otherwise invisible should require a warrant, but I don't mind technology that simply provides eyeballs on what's public anyway. (Note that I feel differently about security cameras in general--they are often pointed at non-public spaces and access should be opt-in on a camera by camera basis. Cameras covering the front entrances, fine; cameras covering back entrances, ask or get a warrant!)