Comment by FeepingCreature

No. Terms and conditions do not apply. Anyone can, at any time, for any reason. Email domains are a historic accident; let's semantically decouple them from the domain system. The tech companies can figure out how to implement that.

The nice thing about a law is we can figure out how to do it after, not before. :)

It wouldn't be difficult! There are 7.6 billion people on the planet, an average email address is probably 25 characters. If every email address is forwarded, that's ~380GB of forwarding data (from address + to address) - and keep in mind that's the stupidest implementation and the worst case possible. I'd like to think that someone who offers a public email service can reserve 380GB of SSD for a forwarding table without going out of business.

Practically, I'd expect vendors to quickly agree on a "301 permanently moved" scheme. So if a Yahoo user is sending an email to a GMail user who moved to a private mail server, Yahoo wouldn't even bother pinging GMail (after the first time) because they'd know that address was moved.