I think SFS has a real waitlist. They definitely do not waitlist everyone.

Maret waitlists everyone, or at least used to.

Wait lists do move in some years when, for whatever reason, not as many kids accept as the school expected (of course the school wants to be fully enrolled in order to get tuition $$). It's not correct that "everyone who doesn't get in gets waitlisted" nor is it correct that a school's waitlist is a fiction -- it just depends on the year. Best chance of getting off WL is for classes that have the most slots available (e.g., 7th and 9th at many schools) as they're the hardest to guess correctly for the schools, especially when they're also big admit class-years for other schools the same kids are applying to.

In my experience, the wait lists are real and there will be movement. But never enough movement to keep everyone happy. Maybe a small handful for each grade?

Tha wait list is real and kids come off the list every year. Just think about it if kids get into all 3 of the schools you just named (that happens too) then two spots will be declined hence two spots will open up. Right now you have to wait until kids accept and pay the deposit once that happens all the movement should start which should be around April 1st. We were wait listed but got into our second choice paid the deposit and partial tuition and then a week later recieved word that we got into our first choice, we ended losing all the money we paid to the second choice and trust me I am not rich it hurt.

My son knew 3 kids who got off the WL for GDS 9th 2 years ago. They have a bigger class to fill than some of the others. He also knew one who got off WL for Maret but apparently that is unusual.

Not to discourage you, but if your DC is WL at any of these schools for any grades, give yourself a few days to remain hopeful then move on. Chances of getting call off of WL is very very small for these schools as they get lots of applicants and therefore put good amount of people on the WL.

What grade OP?

GDS is notorious for having a huge WL that does not move much. Don't know about the others.

Maret's is generally not real, but the others sometimes have movement depending on yield.

Maybe 1-2 kids a year get off the WL is my guess

But it's not like it's a ranked list, there are more factors in plan based on the demographics around the kid who declined. For example, they're unlikely to have a girl decline and take a boy off the WL unless there was a pre-existing gender balance issue in the class.

I think in general, HS WL move very little in all these schools you have here.

We knew of a boy that got in off the waiting list at GDS last year. 2nd grade, I believe.

Some people move off the list, others don't.... If the school is your first choice, send them a letter mentioning that....

are they real or just make us feel better?