What I’m describing does just that. Each character has a medius ID, and (I’m obviously not going to show a full tutorial on the forums on how it works) when you reverse that, and make that ID your own, the player is kicked, but in the process their Gil is stolen.
This exploit was found recently, and the exploit you’re thinking about isn’t the same thing. I like reverse engineering, but I don’t like it when people use it to cheat or troll players online with it.
