If you snuck out, knowing you're breaking the law and will be punished for doing so, that's one more very large barrier preventing you from seeking help.
To get back to what I was saying in my previous post, I had some... unpleasant situations when I was 14. (and many other ages)
But my family trusted me, and I knew that even if they weren't going to be very happy, if I needed to call and get help I wasn't going to face any meaningful consequences for doing so. In fact I was much more likely to face those consequences if I didn't reach out.
So there are a few times I called and got an uncomfortable ride and a few lectures. But I was safe, and I learned how to better take care of myself.
Curfews make kids feel like they have fewer options when things already aren't going well. The curfews certainly aren't in place to keep them safer.
You'll get into the same type of trouble for truancy as for breaking this curfew so I would argue that the curfew shouldn't extend beyond the mandatory education period.
EDIT: That type of trouble being you'll have to go with your parents to see a psychiatrist to see if everything is OK at home.
Through their 17th birthday? You bet your ass I do.
Don't get me wrong I remember what I was like at those ages. But the experiences and pain I had during those years when I had a much larger safety net have paid back many times over in avoiding or safely navigating those same types of experiences without nearly as much support.
I was not always safe during those years. But without those experiences I would have made much more irreversible mistakes.
Eventually children have to grow up, and part of growing up is being responsible for your own health and safety. Robbing children of practice in a safer environment is not keeping them safe, even if it feels like it in the moment.