Just wanted to keep people informed that this exploit still exists. I just tried it today with my own characters.

I made a new rank called "3rd" and gave it promotion/demotion permissions. It is in the 3rd position of hierarchy.
I then changed my alt "Chariots Chariots" to 3rd, and my other alt, Kibbles Katze, to a rank below 3rd, Star Onion.
From there I logged onto Chariots Chariots and was able to promote Kibbles Katze to Onion Knight, which is the 2nd in command position. (You can't promote to master).