They are always very specific when saying that Flock cameras do not do face recognition. Because stated like this it’s true. The face recognition doesn’t happen on the camera (also not license plate reading etc.) instead photos are sent to central servers where they do the license plate reading and face recognition.

You can disable the NFC or USB transport per protocol on yubikeys with the yubikey manager. I can imagine that the nitrokey can do that too. So if you don’t want to use NFC just disable it.