New and interesting network abuse.

My apologies if this strays off topic, but I wanted to share my recent experience. We had a collocation customer come in and request a t1 of pots lines for their servers, then complaints that their "security" software wasn't working because of our RPF checks. As it turns out they were dialing up to a local isp, and sending bulk email using our bandwidth, but the dial-up's ip.... And receiving the TCP ack on the dial up. Very ingenious imho, but I'm not sorry it didn't work out. Anyone else seen this before? -Ejay