Why is the Do Not Track header checkbox off by default?
If the DNT HTTP header has a value of 1, then it is only “asking” the server not to track you. Whether they do or not is still up to them. The default behavior required by the standard is not to send the header. Several advertisers said they would no longer respect it though since Internet Explorer tried to enable it by default.
Brave takes a more active approach and forcefully blocks trackers. This puts the control in the hands of the users and not the servers.