SUBREDDIT: r/AskReddit
TITLE: Reddit, are we being negligent? [story inside]
POST: Throwaway.

One of my close friends has a cousin who is 17 years old who has been dating person much older than her for some time.  Presently, her boyfriend is 24 years old, and they have been dating for almost a year.

**Backstory**:  the older guy has worked at the mall for a long time in a store frequented by the high schooler.  They meet, hit it off, and hung out among mutual friends.  Over time the friendship became more serious, and ultimately, more troubling to the family of the high schooler, but no one has stepped up and said anything.

I've become more worried recently after learning more about the older boyfriend's history.  He apparently had a roommate a few years ago (when he and his roommate were about 20) who also was dating a high schooler.  At that point that high schooler's parents reported the older boy to the authorities and he is now a on the sex offender registry for that state.  Thus, I'm a bit concerned that, even though the older bf has witnessed this, he has no problem dating a high schooler.

The troubling part for the people around this situation is whether or not to act legally.  The age of majority in this particular state is 19 years old, and so the high schooler is technically not an adult until after that date.  The relationship between the high schooler and her mother is already strained by this situation, and so she doesn't want to act.

We have no idea whether they have sex, but have no real reason to believe that they haven't.  **Are we (the friends and family around this situation) being negligent by not reporting this activity to the authorities?
TL;DR: 
A 17 year old girl is dating a 24 year old, and I'm wondering if the friends and family around this situation are being negligent in not reporting it to the authorities.