This is indeed the obvious solution. I don't understand why the EU didn't mandate the do not track flag to be obeyed. I know some browsers already removed it but that was because nobody bothered to obey it. As soon as it can be mandated it will be useful and come back quickly.
Also, there was criticism from the advertising industry that the do not track was on by default but that's how tracking should work in the EU anyway: opt in.
By not doing this the EU keeps getting flak for the many cookie walls.