http://pwp.gatech.edu/admission-blog/2016/03/14/the-wait-list-sucks-part-1-of-3/
Wow, I never thought about it from the administration side. My older son got onto two wait lists three years ago, and we regretted it terribly. He finally got rejected from one college he was wait listed at, in JULY. The other offered him admission on May 5 after we had already payed to hold a spot at a different college. It was very unexpected, (Pomona College in California, small liberal arts college, no one ever gets off the wait list there, we thought, but actually about five students do, and my son did!). Anyway, wait lists are very painful for the student. They leave a student hanging all summer long. Yet my best friend got into MIT in June and said yes, and let her already payed deposit at Cornell U. go. Its just a very difficult process to wait even longer, up to most of the summer for an answer. Think about it carefully before getting onto a wait list. As a parent, its really a lot of anxiety too. Only sign up for wait lists if the student really really wants to go to that university and you have cash to pay for college because financial aid is usually dried up by then.