[bradknowles]

So, the problem I see here is when spammers abuse someone else's machine to conduct activity like this, and all those random people get their IP addresses blocked by your system.

And how would the legitimate owner of that IP address ever know how to contact you to get removed from your blacklist?

[vanviegen]

No, the IP addresses won't be blocked, but the accounts will be reviewed.

Legitimate users would be able to contact us using the email address that is shown right underneath the error message.