Seems like a honeypot to me, telling people to use something other than their home's connection. Kind of difficult to prove. Really seems like they want that information specifically for the purpose of going after those people, since you know, ISP subscriber ID, can't get that if they use the Library, a friend or acquaintance's house, or an Inn or AirBnB, not saying you couldn't track someone down with those if you wanted to, but it's not as convenient.