@quon This seems a bit hypocritical, not of you, but the community, to think this is unethical.
There is a large group of people who block instances that dont block other instances (for example if you dont block kiwi they block you by proxy). They find this information out many ways but usually they just open an account just to test.
The only difference between what they do and what he is doing is they do it manually and then disseminate the information, he does it automatically.
The way I see it, if the information is public, then he has every right to know it.