How to auto-accept cookies notifications as mandated by EU law?

Use an AdBlock Filter

Filter the cookie requests using your preferred advert blocker for Safari and the block-the-eu-cookie-s***-list:

Adblock / Adblock plus filter list for blocking cookie notifications

Add https://raw.github.com/r4vi/block-the-eu-cookie-shit-list/master/filterlist.txt to your filter subscriptions if you want to block "EU cookie law" notifications and popups.

Please note the swear word in the link is required. Regrettable, as the name will limit widespread adoption.

For iOS Safari, Adguard with “I don’t care about cookies” filter works pretty well.

I've written a Safari specific browser extension to do just that called Hush. Since it uses the Content Blocker API it can only block scripts and hide elements, but can't click on accept/reject buttons for sites that force you do so before continuing. That means it can't block some popular sites like Google and Instagram, but on the other hand makes it work with iOS.

It's free, fast, open source and can't access your browser history/passwords.