My statement came not so much from theoretical knowledge but own experience: In the last 5 years of playing ED I've changed my ISP 3 times and it always was the same, as my 24 hour disconnections always showed: When I was still logged in the game I always got the message from the client that my IP has changed. I think in Germany and on a meager DSL line that's a very common thing. But then Germany is still a developing nation when it comes to Internet and getting access to a fiber line is far from being obvious here and not just a matter of cash. What you say might be more common and true for fiber lines, but that I don't know.
In the UK, if we have issues with our routers or the line, we get told to turn our routers off completely for 4 hours and 10 minutes (Sky Broadband and Virgin Media Broadband advice handed out on a regular basis)
Which in turn resets all of our connections and assigns us a new IP. If that does not work, we are told to call back after the 4 hours and 10 minutes and they will reset manually.
I'm not sure why their servers refresh IPs every 4 hours (the 10-minute thing was explained, something to do with a possible delay their end so to add 10 minutes before rebooting "to be safe" it registers the 4 hours), but that is the setup they use.
But as the person I replied to has acknowledged an IP ban wouldn't work due to how easy it is to change it, then this is a moot point.
