What's interesting is that they seem willing to engage with email "cold calls". My spam filter caught one of these on my primary email addresses once. I took the sender's email address, and replied from one of my throw-away accounts and the person on the other end picked up the conversation as-if I'd been an original recipient of his message. So a comprehensive database of sending addresses, fed into a system that produces automated replies, seems like an effective way to disrupt the entire scheme.