For colleges, law schools, medical schools, etc they offer admission to more students than will actually attend school there. What do schools do if more students that were offered admissions choose to go to that schools than they can handle? That is, if way more students offered admissions choose to attend than in the past.
The university I was at faced an overpopulation my first three years. They also guarantee student housing on campus, which 85% of the entire student population uses. They ended up converting dorm study rooms into dorm rooms. I believe many of the newer dorms were designed to make that transformation for that specific purpose, but it really sucked for those guys who had to have their room right next to the elevator lobbies.
They have statistics and history on their side. If by chance way more students enrolled than they expected, they would just have to make room and learn from their mistake.
Back when I was attending college in the baby-boom days, the school actually leased rooms in an old hotel building near campus. The hotel owners didn’t care, because they normally filled those rooms only on football weekends.
When my sister was going to school at BU in the late 70’s they had way too many students accept. They created temp dorms in the common rooms, then instituted “forced flunking” to trim down the roles by the end of the first term.