Security cameras can only be considered as passive devices for protection, unless they are hooked up to a motion sensor automatic alarm system, OR, some person is constantly monitoring the camera feeds. In that case, if anyone suspicious comes into the field of view, the local gendarmes can be immediately summoned to check out the situation. Otherwise, if you have a recording device attached, the crime will still be committed although apprehension of the suspect will be far easier since they were caught on camera.