Faces no, as other people have said - except, what about integrated systems that combine ground based CCTV with satellites, or drones? You might only be able to

Faces no, as other people have said - except, what about integrated systems that combine ground based CCTV with satellites, or drones? You might only be able to see someone's head and shoulders, but that's good enough to follow them as they walk through a crowd, and you can use that to decide which CCTV to use. Presuming it's all networked and accessible, but that might be the case at some future point.