you cant loose your acc by exchanging, even that the other user knows reverse engeneering and is hacking you trought exchange... I mean he can know your ip with eschange... so that opens like millions of hacking possibilities.. Just need to proof your ports and vulns! But lets get to the main point here! When you exchange with someone, if he uses packet sniffers and a dos console, he can know your ip, and pk edit the stuff you think he is trading with you, so like he shows you a sun weapon in xchange window, but in reality he is putting there a stack of arrows, and you give your legit money for it... All this is because when you trade stuff via exchange, you are not sendins the itens description to main JM server, but directly to the other client, and vice versa. So its possible to be "scammed" more than hacked trought exchange... Not safe so no use!!! Use stall to sell itens ;)