A couple weeks ago after we noticed an email/password check bot running against our service. It was going through the list of emails from the Adobe (we didn't decrypt passwords though, just emails match). The bot itself was blocked by our system but we emailed our users that had their email/password tested. The funny part is that the bot had a bug: it followed the returned 302 redirect. Since it was coming from China's IPs, we started to reply with redirects to www.gov.cn and the bot stopped in about an hour after that. Obviously, someone got a visit from China's KGB :) :) :)
