And how is it being F2P any determining on it's validity as an example?
Also, Ultima Online and Darkfall Online aren't free to play.
It's never been a rule set in stone, and even if it was (and it's not), nothing says that rules established by OTHER games cannot be broken/revolutioned/changed.
Eorzea is it's own world. FFXIV is it's own game.
PS: It doesn't make ANY sense that a piece of armor just refuses being worn. It's an *artificial* limitation that has nothing to do with "making sense"