There was some type of "inappropriate sexual contact" between a 17 year old boy and a 14 year old girl on a band trip. But we don't know the act, if they were boyfriend/girlfriend, or whether it was consensual. Does it matter? For the band director, heck yeah. (Note: news stories will always call it "abuse" or "assault" even if the act is consensual if the act still constitutes a crime.)
And "abuse", by definition, includes consensual sexual contact with a person under 17 by someone three years or older that that person. But if all the band director knows is a 17 year old and a 14 year old are have had sex, does he have "cause to believe" that the law is being broken? For all he knows, she might be 14 years and 11 months old and he might be 17 years and 1 day old. If that's the case, the kid is safe and no crime was committed. The Penal Code makes it illegal to commit certain sexual acts with a minor who is under 17. But if the minor is 14 years or older, it's not a crime so long as the acts were (1) consensual, and (2) the accused is within three years of age of the "victim." So if the acts were consensual, we don't even know if the 17 year old committed a crime until we get a calender out. (Being three years and 1 day older takes you outside of the statute.) And I don't think you can expect a band director to know the details of the law. It could be that he didn't think it was a crime at all.
So until we know what the band director was told, it's a little hard to judge him. But I'm sure he's not feeling judged today at all.
Edit: Here's the statute.
You guys feel free to convict the band director under those circumstances, but I won't. (And, to further complicate it, he would have the additional defense that, regardless, she wasn't "adversely affected" within the meaning of the statute.)
We're not talking about whether he broke school policy. We aren't talking about whether he should be suspended. We aren't even talking about what is the morally correct thing to do when he learned of the conduct. We are, however, talking about the government trying to convict him of a crime for not reporting. It's easy to forget that he didn't touch anybody.
But if it's non-consensual between the two kids, the band director has trouble.