The University of Chicago has a General Waitlist form that you can complete during Orientation week, whereas Lafayette College has an email contact for housing waitlist requests. At Emerson College, you go on the waitlist if you submitted the housing deposit but did not meet the residency requirements.
The University of Chicago's College Housing division randomly mixes General Waitlist forms from first year and transfer students to determine housing sequence. Once the housing division makes it to your name in the queue, you have 48 hours to accept the offer or you lose the room. There is a certain amount of freedom to choose housing preferences in the queue without losing your placement status. Towards the end of the autumn and winter quarters, the waitlist freezes for a time.
Lafayette College uses its waitlist to assign rooms of its choosing to students on the list. You are put on the list if you did not receive the initial lottery assignment. The school has strict deadlines for housing applications that are published online.
Emerson College manages its waitlist through its Office of Housing and Residence Life. Housing on campus is not guaranteed for all on the list, but office workers can still discuss housing options.