I never understood this. Parents tend to get off work around 5-6, right? Schools were so adamant, in my experience, about getting kids out of there (and sending all the staff/faculty home) by 3:30. This is at every grade level, including those where the students can not yet drive. This also means that there's an extra need for school-provided transportation (busses). The need for more than half of the student body to ride busses feels like a huge process smell to me, both in that the city should be providing transportation and that the school is requiring students to come and go at times that are too inconvenient for everyone.

Why not, instead, shift the school end time back to 5:30? Instead of 3:15 (as it was for me, though I'm sure it varies), this adds 2 hours and 15 minutes to the day. As a result, the academic day can begin at 10:30 rather than 8:15. Labs, libraries, etc can all be open during this period to allow students to catch up on work, get help, etc if they wish to come in early (or need to due to their parents' work schedule). The cafeteria could even open on a limited basis to serve breakfast in this time. But there's no rush to get in class by 8:15 and no need to start serving breakfast at 7 AM or earlier.

Then athletics can start early (say 6:30-7) instead of running excessively late. And further, the school can remain open in the same state it did for morning for these students and others who wish to stay late and work on their assignments.

I felt, in HS, so rushed to get in class, "learn" (hard to do when you're constantly moving from room to room) and then get out and do all the work at home. Ok that's fine, it was convenient for me since I was able to walk home in just 5 minutes, but for most people I suspect this was a horrible pressure. And for people who don't have access to everything at home, this is also probably damaging to their ability to complete work, and likely discouraging. Not to mention distractions, etc.

I really liked how it was in college. Because I had to commute, I tended to stay on campus later. I didn't have my distractions (home, games, computer, etc) with me, so I'd end up just doing my work or research. Then when I went home, I had nothing but free time. Time I spent reading articles on hacking, watching defcon videos, chatting in IRC, playing games, reverse engineering, etc. All tasks which I thoroughly enjoyed. All made possible because I had a place to work separate from my home. So the notion of "home work" seems broken to me. Totally broken. There needs to be work/life balance, and part of that includes a separation of "home" and "work". I never felt that in HS.

I found it really strange that morning detention was incredibly productive. I had the pleasure of receiving this once in 7th grade. I brought a book and read half of it in that time. In fact, working was required, no talking. Otherwise I would've been just standing outside goofing off. There was no place for us to go like that at the school to be productive. We had to stand around outside until classes started. And you realistically had to do that to be on time to class. Doesn't this seem odd?

Also interesting was the partial schedule I had in my senior year. I had a calculus course that began at 11 AM, which means I got to sleep in most days of the week. I would often go to school at 10 AM and go sit in the library and read or go over my work, then go to class at 11. I don't think I ever received a B on anything in the class (sure, it was easy, but this was statistically anomalous to my other grades, I never did homework at home; I always did it on campus, and my grades reflected that, and I didn't care because "home" was not a place to do work). I also got a perfect score on the Calculus BC exam and skipped multiple college courses as a result. And because of that experience, I realized I enjoyed math far more than I had previously thought and wanted to learn more, beyond Calculus, and so I ended up getting a math degree.

Are there actually any negatives? Sure, the pay for teachers needs to be increased to justify spending more time at school, and even more than that, it should probably be doubled or more realistically because there's currently no economic incentive for the smartest people to teach. But that's an existing problem.