It's not an artistic work, and there are broad rights to images in public that preclude you from making a work on your face to prevent imaging of it.
It's a nice idea but it would allow lots of law breaking of things worked that way. Eg paint something on your car, now police can't capture you on speed camera!!11one.
Yes sadly that is the crux. Whilst the people do have concerns, those concerns are shared for nefarious reasons by your criminally inclined.
Way things are going, how long until we have camera technology as CCTV that is comparable to Holywood camera's - certainly the standard today is up there with 80's offering.
Might even come a time when you can do a film in places like London without needing any cameras as you can just ab-use the data protection act to get copies of any footage your in and get all the camera angles and video you need to edit into a film. Kinda doable now, though not all cameras are 4k and well light area's. But certainly doable.
One interesting legal aspect about CCTV in the UK - the only camera's that are allowed to record audio are the ones located outside police stations. Which is reassuring as with mic-arrays - intrusion into privacy and indeed voice recognition would be far greater than any CCTV/facial recognition. But that is one to watch and keep an eye upon as I'm sure that will change/erode over time.
It's a nice idea but it would allow lots of law breaking of things worked that way. Eg paint something on your car, now police can't capture you on speed camera!!11one.