Kouchisei knew Toshimi liked baseball, but unlike her and apparantly some people from school, he wasn't familiar with the arena - this included where to walk, the toilets being too far away not that he knew where, and the price of eating. He'd never really bothered going to a sport game. If he wanted to see people blow hot air he could do it cheaper by watching at school.
He didn't know why Kozue wasn't wearing the paraphanelia, either. It seemed her level of establishment, and the fact she would have like something so different would have made him more comfortable about being around her.
And those team clothes made him uncomfortable too. There was an electric charge hanging on the air, which made the evening somewhat better as he said hello and took a seat two away from Kiriko's right. She was just a little bit intimidating.