I don't know, it seems to me this "open proxy" thing is just a chimera.
Right now, as I write this, I have my choice of 5
different IPs I could be
posting under - seems my neighbours aren't quite as current in keeping their
LANs secure as I am. For all I know, one or more of them could be TORs or
other open proxies. Sometimes, when my own LAN is acting up, I'll wind up on
my alternate LAN - two doors down - without even trying. For that matter,
most people working on LANs depend on their system admin to set up the
internet connections - and would have no way of knowing that they were
accessing the web through an open proxy. And of course there are the signal
stealers - endemic here; the hotspot users; those who use publicly
accessible internet connections (Internet cafes, libraries, etc); and some
cities are already offering internet access just by sitting in the local
park. My usual ISP never gives my city of residence; and if it was traced
back, it could show up as any one of five cities - and I use one of the
biggest ISPs in my country. The IP from which someone edits doesn't tell
anything about who they are, where they are, or do anything to provide any
kind of unique "fingerprint." I really don't see the point.
Risker