Maybe we could call it something like "DoNotTrack", to get the idea across.
DNT was mostly ignored, but if it had the weight of law behind it, it could still be great.
Some places still respect the header. Medium does - you'll get the warning for embedded content.
Properties should be defaulted to what is most likely user desire, I think. So for DNT this would mean “true.”
It was ignored because companies that make money from tracking also make browsers and web sites.
Advertisers couldn’t care less about privacy.