From the practical point of view, I am afraid the trackers will respond a way if such a move is made on such a global level. Nobody was fighting AdBlock+ when it was only used by geeks and now as is it has gained so much attention there are a lot of sites that won't work if you use AdBlock+. Introducing te "do-not-track" header was a great idea but it has been completely ruined by major browsers turning it on by default so the trackers have legitimately chosen to ignore it.