<respectfully snipped for brevity>
When I was in the dorms there wasn't exactly a head count, but each dorm had a Resident Assistant, and then each room had a Room Leader. If anyone was missing from the room at curfew (10:30 when I attended) or especially lights out (11:30 when I attended) the room leader would notify the RA. If a student was expected to be out past these times the RA would be aware of this information. Given that BS's job sounds like a landscaping type job I can't imagine that would apply to him, unless he had some second job that hasn't been reported (I knew a lot of students who worked at Chick-fil-A, for example, and helped close the store each night).
So, as a likely example, when I was a student the way this would go down was if my roommate wasn't at the time by say 11, my room leader would have reported this to our RA, who would have tried to reach out to the student directly and if that was unsuccessful then by 11:30 or definitely by midnight the RA would have been on the phone with school security (which was kind of laughable but did exist). I'm not exactly sure what the procedure would have been after that. I can't recall a time where this ever happened when I was a student. But suffice to say these aren't the kinds of dorms where you just come in at whatever time you feel like in the middle of the night or don't show up at all -- a student not coming back to the dorm would have been a major, major issue and I would assume that by 2am this would have been known by the highest levels of college staff (not sure if Dr. Sexton himself would have been woken up for this, but it's possible; I understand his age/health might have changed things by now, but I suspect he would have been when I was a student).
I know how odd and overprotective it sounds that a parent might be checking their 20 year old kids whereabouts on a Saturday night, especially one enrolled at a Bible college, but in this environment this isn't very weird. I had a lot of friends at Crown who had parents who would have behaved this way, and their kids also would not have thought anything of it. I'm not saying BS or his family fall into this category, but there is nothing surprising here. To clarify my previous paragraph, and as I think cjk mentioned elsewhere, Crown students are required to stay in the dorm every night. Unless something has changed this is a pretty strict rule; you aren't allowed to go stay with your buddy across town or anything like that. If I recall correctly the only exception was if your family was visiting town and you got written permission then you could stay with them during that time. It was also very, very difficult (almost impossible) to get any kind of permission to spend a weekend out of town, even to go back to your own home/church. Except for breaks (only Christmas and Thanksgiving, not even Easter) and "ministry weekends" (which occurred once per semester) or some kind of organized school ministry trip, you stayed in the dorms every weekend, no exceptions.
