Congrats on a great inspection! !
When I had my inspection my inspector said the same thing, that I need to have a smoke alarm in my family room if the kids sleep in there. They don't, but she made it clear to get one if they do. It does make sense, we had a house fire a year and a half ago that started in a shed that was connected to the house on the family room side(don't ask me why, it was here when we bought the house, 3 years ago) and we did have detectors in the hallway, but none of them ever went off-that we heard anyways.