I know several people who had last minute pulls off wait, just a day or two before orientation or classes. Several years ago I had a call from an advisee who had becoming more and more depressed as the cycle went on and no WL call. She called me one day in the first week of August and literally was screaming that I first assumed she had a breakdown from not getting in. Took me a few minutes to understand she just got a call to be accepted and now had to move out of state and be in class in 72 hours.
A clinical teaching doc I know at an Ivy got called from his state school in Chicago, near where he lived on a Friday to be accepted for class beginning that Monday. This was in the days before cell phones. When he got there and working with the admission director to get all the paperwork in during the first week, he asked how they had decided on him the last minute. They simply went down the wait list calling who was closest to the school and he was the first one who picked up the phone.