I file this under “you can’t have a technical solution to a social problem”. We can do all we want to protect e-mail, but when it comes down to it, someone is going to figure out a way around it and ruin it for others.

The current situation is that we have technical solutions for authenticating smtp sending domains. But there will always be someone who flags an email too quickly or just wants to spite you. And so we’re back at square one.