Full dates and the waitlist
How families get offered a spot when space opens.
When dates are full, the new-reservation screen says so and offers Add to the waitlist with the same details. Families can also join from their portal.
When space opens, the oldest waiting request that fits gets a 12-hour offer by email (and text, if they've agreed to texts). They book it from the link, or you book it from the Waitlist page.
Requests nobody confirmed let go of their space once their first day passes, or after the hold period you set in Business details. The family is told, so the space can go to the waitlist.