The student paper here at Georgetown ran an article a couple years ago about the incidence of sex in the library study carrels. Several floors of the library have small rooms around the outer walls, some less than 8 ft. wide and maybe 10 ft long, some a bit bigger, for use by graduate students and faculty. Inevitably, people go in there with their enamorata and get it on. I don't know how many undergrads have access to the carrels, unless they were the "guest" of a researcher, but it hardly matters; no reason to think the grad students and faculty are immune to the allure of convenient sex. Got to remember to hang your coat over the little window on the door, however.