Board Thread:General Discussion/@comment-30231626-20161015043220/@comment-4010415-20161016012155

ChishioKunrin wrote: Whether we like it or not, we have Miles quoted as saying "That's his true symbol." Since the video hasn't really been linked here, here's the link.

Monty: It's nothing spectacular.

Miles: It was just something we arbitrarily chose. You (Monty) were like "What about this?" and I was like "That's fucking awesome."

Monty: And then we put it on everything he wears, I guess.

Miles: A little bit-- Not everything.

And then before Monty could say anything further, they got sidetracked into talking about Jaune's shoes having "Left" and "Right" written on them.

So, it's not that they arbitrarily decided to give him a hidden symbol. They arbitrarily chose that particular symbol to be the one hidden under his chestplate.