I think you'll have to bring it up - it would make you look suspicious if you didn't. Kazuki was there with you after all, right? And while I don't think he's out to get my team, I also don't know who else he's mentioned it to.

...Shu is planning to mention the pin himself, I think. He's acting like he has nothing to hide, so I'll do the same. But... I do have a plan for if it seems like people are doubting him.