If I hadn't already deleted all my posts and comments, I'd be poisoning all of them. Randomizing numbers, switching units, changing names, etc.
No, there are still use cases for it. I usually use it to retrieve web pages from sites that get incorrectly blocked by the firewall at work.
If you have admin portal access to write transport rules, I recommend writing a rule that has the server reply with a 550 5.7.1 Delivery Refused error. Trigger it based on the keyphrases "top of Google search" and "affordable SEO" to start with.
And once again, he started zapping.