When you inspect somebody, there's always that same background behind the knight. I hardly ever notice, myself, but this is basically a crown sink idea. The idea is you could buy/unbox a background that you can activate and people see that background when they inspect you instead of the regular default one. Whether you see the one you picked on everybody, or you can see everybody's own custom background theme, I just thought this was something interesting (or most likely very, very pointless) to put up.
[If there is already a thread about this, believe me.. I looked.]
Here's one: http://forums.spiralknights.com/en/node/64740
And another: http://forums.spiralknights.com/en/node/62412
Essentially, surewhynot. Can I have Luguiru's paycheck now?