It isn't related to duplicate accounts as such, but more the ip addresses.

I was under the impression that someone using a public network such as the one on the GNE buses, McDonalds, East Coast trains etc shared a common network ip.

Similarly, those on a mobile network shared one too.
When I googled the ip my device was giving out, there were literally hundreds of pages relating to that ip and how common it was.

Just a scenario here, but say one of the suspected duplicate accounts was surfing the net, using the wifi on a Go North East bus.
I then happen to board that bus, log on in my phone, one of the mods happen to be checking the ip's after a post like the one from idiot and voila, I am suddenly a suspect in duplicate profile gate.

My next question was related to locations of ip addresses.
Based around the settings I have on fb, I get an email when I log in from a new device.
When I was on the three network for a dongle and it was installed into a new machine, fb notified me of a log in from Slough.
Checks revealed that the log in was me, when sitting at home in DH4 7 - a good few miles from Slough. The Slough connection came from where three were based (or something like that).
So, getting back to my point, can our ip addresses be traced to a specific location and if so, how accurate is it?
Will it locate where I am sitting now (if a mod wishes to share my location at time of posting) or will the system give a generic location according the network I am using?

edit: Just found the ip address my mobile is giving out now.
It has traced the owner and the location varies between central London, a field near Skipton and just off the M74 near Lockerbie.
The owner is correct, but I am nowhere near either of those locations.

The other points/questions still stand and are genuine ones.