Hello!
When I was in high school, I went to a boarding school where lights out was 9:30 freshman year, then 10pm through junior year, and then senior year there was no lights out time. The nuns would come by 15 minutes before lights out and knock on the door, and then at lights out, they'd come around and turn the lights off if you hadn't already done it yourself. That was during the week. On Friday and Saturday nights, they did not enforce a bedtime - although most of us didn't burn the midnight oil, because... hello... girls' school! What would we have done staying up late anyway?! When I went home on vacations and for summer, my parents enforced a 10pm curfew (famous quote from my mother, "Whatever you can do after 10, can just as well be accomplished before 10!") but once I was home, they didn't make me go to bed. It might have been different if I hadn't had really good grades and generally been a good kid.
But all that being said, I don't think there's any reason for kids to be staying up past midnight, probably. There's something to be said for totally screwing up their sleep patterns, and no matter what they say, they still NEED sleep! Their brains are still developing, they're still learning at an incredible rate, and it is good for them to get sleep during night time hours. At least that's my opinion, as someone who has always enjoyed her sleep. =)