If you're new to the dance community, then the idea of not selling someone a ticket straight away for an event that hasn't sold out might seem strange! However, this is a practice that has been used for a long time by dance organisers.
Keeping a sensible balance between leads and follows makes for better dance events, particularly lessons. Imagine a lesson that can be attended by 50 dancers. If there was no control over how tickets were being sold, the lesson could end up with 45 follows and only 5 leads.
On DanceCloud, a event organiser can choose to sell tickets in a way that ensures they do not end up with too many dancers of one role. If (for example) follows are signing up quicker than leads, it will stop selling tickets to follows and instead offer them places on the wait list. As more leads sign up, DanceCloud releases tickets to follows on the wait list. This helps maintain a healthy balance between the two roles at the event.