Now this didn't sit right with me. Some dude from across town fat-fingered his IP assignments a couple of years ago and stepped on two of my 'assigned' addresses. I've seen traffic from all sorts of hosts on a bunch of different subnets flow by. So I decided to conduct an experiment.
I have four static IPs assigned to me, but I'm currently only using three. Last night when we were playing real estate refugees (5:30 PM showing) at my folks' place, I configured my laptop with my spare IP and plugged it into their cable modem. At first nothing, but after resetting the modem, viola!. I was cruising around on the 'net just fine. I repeated the experiment again today at my in-laws' place. Same result.
I am now pretty sure that the entire town of Glastonbury is served by one node. I even know right where it is: 1000 Chestnut Hill Road.
Because I have the Virgo nature (in spades), I decided to do a packet trace to see how flat is it?. The table below is populated from IP ARPs seen in a ~1000 frame capture (that would be Wireshark to Access to Excel to HTML). Cox is currently multinetting approximately 25 different IP subnets across the local wire. I could grab an address from any of these 25 subnets and just start banging away ... or intentionally grab someone else's address and hose them. I don't mean to be critical of the pros from Atlanta, but that's a mighty loose way to run a railroad.