[litenboll]

The important part here is that it's at the browser level, IMO. Then it's the user's choice to either reject/accept all by default or get prompted once per page. I'd guess that 99.9% want to set it globally and never think about it again.

[cynicalsecurity]

It's been on the browser level for ages. It's the DoNotTrack http header. The websites simply ignore it and hope the users will simply keep pressing the consent button.