The class is full but people still want in — is there a waitlist?

Yes. A prospective student joins that class's queue, and once a seat frees up, staff offer it to whoever is at the front. The offer is sent to the parent through the message channels with a deadline to reply — three days by default, adjustable per offer.

An offer not answered by its deadline expires, and the person returns to the back of the queue with the attempt recorded. Offers are always a staff decision, never automatic: a free seat has often already been promised in a conversation the system knows nothing about.