I think there are already some blocking lists out there, but that seems like a silly thing to waste time maintaining given neither web master or user wants them to exist in the first place.
Then someone outside the EU could block everything that starts with "legal-eu-" to get rid of everything added to comply with EU law, and someone outside the US could block "legal-us-" to get rid of everything added to comply with US law.
(Do the major blockers allow blocking based on a prefix of a class name? If not, the same effect can be achieved by giving the element multiple class names such as "legal- legal-eu- legal-eu-cookies").
People might want to block by subject regardless of what jurisdiction's laws caused something, which suggests there should also be "legal-gdpr-eu", so if the US passes a similar privacy law someday that could by "legal-gdpr-us", and someone could block "legal-gdpr-" if they don't want to see any of these kinds of notices. But the US probably would not call its similar law "GDPR", so may it would be better if instead of "gdpr", we start with "legal-eu-privacy-gdpr" and "legal-privacy-eu-gdpr"? Then a similar US law would get "legal-us-privacy-x" and "legal-privacy-us-x" where "x" is whatever tortured acronym name Congress comes up with. (And probably cookies then belong under legal-eu-privacy-cookies).
This is getting complicated enough that it might be better to go to some kind of tag based system, with tags implemented by class names of the form "legal-NAME-VALUE" (for now, I'm assuming this is all for blocking regulator imposed legal notices, hence all tags started with "legal-").
Tags that might be used for the earlier examples include:
legal-jurisdiction-eu
legal-jurisdiction-us
legal-category-privacy
legal-category-children
legal-law-gdpr
legal-law-dumb_us_acronym
legal-law-cookies
legal-law-copra
For this to both be useful and not become an ungainly mess to deal with, it would need probably be carefully thought out beforehand, and have some group maintaining and managing a registry of supported tags, and making sure any additions to the list are well thought out and consistent. It could be a lot of work.