I've seen several people mention the Do Not Track header, but it comes with a downside: it paints a giant target on your back. If, say, 5% of user agents have

I've seen several people mention the Do Not Track header, but it comes with a downside: it paints a giant target on your back. If, say, 5% of user agents have DNT enabled, then it's becomes extremely effective as a fingerprinting vector on the people who specifically don't want to be fingerprinted. If, on the other hand, a majority of people use it, then most people will simply ignore it or perish. This is mostly why people ignore it nowadays, because IE turned it on by default. No one uses it anymore because there's no reason to trust that it'll do anything and no reason to actually follow it.