@Lugdu
Not comfortable saying where I live online, but since inconsensual kiss is a reportable sexual offense, the school would have to report to police, and they may be involved. And to be put simply once you get involved with the police as a suspect here, your school life is done, even if you don't get a sentence, which is the normal one for cases like these.
Schools here care more about how they look compared to their actual students, so the last thing that they want is any kind of bad rep from police involvement, no matter how small it is. It's not good, I know but that's how it works here.
But this is Japan, where even chikan doesn't get reported, so I do understand and you do have a point.
Btw I'm not worried about koharu, nor did I condone what she did in case you misunderstood me. All I say is that I can still relate wanting someone who's in another relationship, whereas I definitely cannot relate with inconsensually kissing that person when she's in a great relationship, not to mention with my best friend. Can't relate even if I'm dead drunk.