I haven't used a Shenandoah hut in over a decade, but I would like to do a one or two night AT hike in SNP and I would like to use the huts. My reading indicates that they are reserved for the use of long distance hikers, where long distance is more than three nights out, IIRC.
Do the rangers care? Is it an issue? I'm planning to go out over the holiday weekend in October, so there will be more hikers than on other October weekends, but not much in the way of thruhikers.