I went to a high school that had a college-like schedule with the campus covering a few buildings in downtown (small city). Attendance wasn't mandatory, grades were exam/deliverable based.

The freedom was great for high-achievers. Normal students showed up to classes like normal. Almost-dropouts didn't go to class and waste everyone's time (eventually they were transferred to regular high-school).

I learned valuable life-lessons compared to the hand-holding and babysitting done in other high schools, and highly recommend the model.