At one point in high school, the city I lived in had a curfew. It was in response to something, I don't remember what, and I don't remember what time it was since my personal curfew was always earlier.
I do remember that it did not apply to teens that were on their way home from somewhere like work or hanging out with friends. It applied to kids that were loitering in the streets after a certain time. I don't have a problem with that.