Currently when a player creates a world using WorldSystem it also creates a folder over in WorldGuard which is fine. However, when a player deletes there WorldSystem world, it unofrtunately doesn't delete the folder over in Worldguard. This could cause some pretty big issues if you have a large amount of players loading/deleting worlds....
Not sure if this can be implemented so that when the command /ws delete (player), the plugin also checks for the plugin WorldGuard, if its found it then detects the same WorldID and deletes it? This would be a big help...