What would happen?

Wrong. Smart zrun organizers record the ranking of each one of the buyers, so no matter if they name change, server change, etc, we will find you

Who cares that much, and what are they going to do? I'm sure if you levelled really fast a couple of times or lost a lot of exp, the task of keeping track of that character would be impossible. Most 2nd job and 3rd job characters can easily move thousands of ranks a day. I'm not advocating stealing from Zakum groups, but people who make threats like that are way too full of themselves.