Privacy

The GDPR kind of does the job that DNT could have done, if that's what you're thinking of...? Tracking generally needs to be opt-in for EU citizen, so you don't need to send a cautionary opt-out signal anymore.

Admittedly, the "most jurisdictions" is me guessing, based on how I expect laws to work in most countries. As in, I expect most countries to have some law that says you can't take someone's data, if they don't want you to take it. And then tracking is/was somewhat of a grey area, because companies argued that tracking is totally in the interest of users, like, who doesn't want to see personalized ads? But yeah, if you then remove any doubt by sending them an opt-out, then it's most definitely not a grey area anymore.