Our middle school here had that kind of schedule (8 classes of 42 minutes, actually). Though, in the high school's case, five classes is more than they used to have before switching to trimesters. That extra 25 minutes felt so long at first, but then I realized I had less homework, which was awesome.
My school didn't allow for open periods. Then again, there were only 5 class periods in the day (hour and 10 minutes each), and the year was split into Trimesters, so there wasn't really room in schedules to allow open periods.
It's part of their "integration" classes, most likely, which are supposed to help them get ready to live on their own and have an actual job. They'd be completely unprepared otherwise. With that experience, they're only somewhat unprepared.
When you become an upperclassman, though, as long as you have a job, you can see if there's a work experience program that's open to all students that allows you to get out of school early to work for a class period or two at the end of the day. I know they had something like that at my high school. I'm not sure how widespread such a thing is, though.