The Z list is a different thing. Some waitlisted applicants a given a place on the Z list, which means they are guaranteed a spot for the following Fall, but need to take a gap year. Again, no Spring admits
Even when waitlisted applicants get an offer off the waitlist, they only have a few days to confirm; there is no dog-and-point show and tour. If they want to visit, it’s on their dime,and the visit would basically need to be the next day.