As far as I know it is to prevent counterfieters from going to the shop and copy legitimate codes without purchasing, hahaha ...... that is what my friend who knows a Yonex salesrep once said.
The logic is that you should buy Yonex racquet with Sunrise sticker covering the cone serial code, if the Sunrise sticker does not cover the cone code then it has been tampered and not from Sunrise. As far as I know, it is done INTENTIONALLY by Sunrise. BTwW, if the Sunrise sticker is somewhere else then it has been 'tampered' that is what I was told