Every fan gets a number, in sign-up order. When the city hits its threshold and the concert is confirmed, the first to sign up get the ticket link first, ahead of the public sale.
Email, phone, how many tickets you'd take and the most you'd pay for one. No payment, no obligations.
#0001, #0002, #0003: in sign-up order. The number stays yours.
When the concert is confirmed, the ticket link reaches the first to sign up first, in number order. Tickets are bought from the organiser.
UNBOOKED doesn't sell tickets and doesn't set prices. Signing up is a declaration of intent, not a booking.