There is no personal data collected as it's one of the key feature of that process, so in my humble opinion it's out of the scope of GDPR.
I don't see the word "personal" in this sentence, only "any data collection". It's clearly not in the users' interest/benefit to activate this data collection, and not required for the normal functioning of the browser/websites. So activating this silently is minimum _very unethical_ and probably illegal, but I'm not a lawyer.