A while ago I sent a ticket to the team regarding this issue: Why privates can wear commander gear. and when I lost my Knight rank i wasn't able to equip the ring I had recently purchased.
The second age of pvp was a blessing for those low lvl warlords that were able to start pvp again with their commander gear, this way there was no living private that was able to defeat them (Unfair)
Seems like KI didn't notice that they changed this feature (not being to equip them if you dont have the rank) for small items (rings, athames, amulets) leaving behind the most important of all: the commander gear.
So, rank to buy it or to equip it? they need to change this and for all items not just a few :o and i hope it is to equip it ~