About 150 to 180 students of the more than 5,000 undergraduates at Princeton take a leave of absence each year for various reasons, university officials said. In three to five cases a year, the university asks students who aren’t considering a leave to consider taking one — a practice disability rights advocates consider coercion. If the student refuses but the university determines their safety is at risk, the student can be forced to leave. Princeton says this situation has not occurred in the last five years.