Sometimes a gmail user sends me an email. I object to that. In principle, I need be able to tell Google that I do not consent to them processing my personal data whatsoever.
If one of their users addresses an email to one of my email addresses, I do not want Google to store the message or even transmit it. They must refuse to handle my personal data, and thus refuse to process email traffic involving my email address.
I believe this falls under GDPR Art.18 or 21. But the question is, how can I submit my GDPR request to Google? I can write them a letter but I do not want Google to get my address. I don’t even want Google to know my name. The only thing I want Google to know is my email address, so that Google’s mail servers can refuse mail to that address. But the mere act of submitting a GDPR request inherently requires data subjects to prove their identity to data controllers.
And that's why I'd like to get a court ruling on this. Would be quite interesting.