In most cases, Yes we can tell by IP. But in other cases Sure they will hide behind proxy or vpn. But we have other ways to find out.
a lot of people ask why don't you just ban them once we find them to be Ghost.... In some cases we want to see what their plan is... meaning, did they come back to start trouble Again ? or are they back and their plan is to behave ??
So Yes, if they don't cause Trouble, we will let them stay... give them a 2nd chance... a few have had 3rd chances.... some just come back and we will never know they were trouble makers before...
As far as RunMaker .... he's not JC unless he Moved out of his State