DD took a study half (not at Blair) one semester of sophomore year. I think in general the counselor has to sign off on any course schedule so this may just be part of the normal process.
It is an actual class, you can’t have a free period. The class is graded but all DD had to do is show her planner and maybe answer a couple of one sentence questions weekly. It is graded and shows up on the transcript as a non-honors class.