I feel like I'm starting every sentence with something along the lines of, "back in my day..." but... when I was in college, I lived in an off-campus apartment. My roommate and I each had separate bedrooms. We both had boyfriends. Both of us spent every night at our respective boyfriends' places and it was a happy surprise when we ran into each other at the apartment. We had to actually make coffee dates to see each other. I could have otherwise gone days -- days! -- without seeing her. Same with all the rest of my friends. I would have seen at least one or two of them every day, but there was no single friend I saw every single day. So, it would have taken a week to raise the alarm, in all likelihood, if I disappeared (at least if my boyfriend had been the one responsible -- otherwise, I like to think he would have said something to someone). Students tend to have weird schedules and are very busy. They are always surrounded by people, but not always consistently the same people.