I don't think I ever recall being bothered by noisey hikers at the shelters - even during peak season. I think that the shelters areas are remote enough to discourage party-ers from coming in. Also, on busy nights a Ranger will sometimes stop in to collect fees - which will put a damper on rowdy behavior.
If your hike is during mid-week, I would not be surprised if you are alone a few nights. Weekends get a little busier.