The Do Not Track header didn't die because of an arms race, it died because there wasn't any legislation making it criminal to track people who had explicitly indicated to you that they did not wish to be tracked.
Kids (especially ones close to the age of legal access anyway) will try (and succeed) in bypassing any sort of restriction on adult content including any of the digital ID garbage. There are any number of software scams targeting everybody, and your hypothetical just be another one; I doubt that it would increase the total number of such scams.
But requiring sites with adult content by law to require what would sort of be the opposite of Do Not Track flag (Let Me In?) would at least mean that kids would have to do something illicit on the client side to access adult websites that they would have to hide from their parents. If you made sure their phone or Chromebook was nerfed, you could make sure they couldn't install extensions or software that added the flag, you could strip it from their network requests; you could even strip it at the router. [edit: you could even opt-in with your phone company to strip it from your kid's phone's network requests.] You as a parent, and people who have nothing to do with kids, could trivially opt-in.
> The Do Not Track header didn't die because of an arms race, it died because there wasn't any legislation making it criminal to track people who had explicitly indicated to you that they did not wish to be tracked.
That was the first big problem. The second was that some versions of MSIE set the header by default, without the user having taken any action to request it. This made it infeasible for any major web sites to honor the header - by doing so, they'd break functionality for most MSIE users. (MSIE was, at the time, still the dominant desktop web browser.)
Kids (especially ones close to the age of legal access anyway) will try (and succeed) in bypassing any sort of restriction on adult content including any of the digital ID garbage. There are any number of software scams targeting everybody, and your hypothetical just be another one; I doubt that it would increase the total number of such scams.
But requiring sites with adult content by law to require what would sort of be the opposite of Do Not Track flag (Let Me In?) would at least mean that kids would have to do something illicit on the client side to access adult websites that they would have to hide from their parents. If you made sure their phone or Chromebook was nerfed, you could make sure they couldn't install extensions or software that added the flag, you could strip it from their network requests; you could even strip it at the router. [edit: you could even opt-in with your phone company to strip it from your kid's phone's network requests.] You as a parent, and people who have nothing to do with kids, could trivially opt-in.