What does early bird ticket out-of-stock registration mean?

The meaning of restock notification. According to the query on Ctrip's official website, when early bird tickets are out of stock, users can choose the early bird ticket out of stock registration option. Users can be notified via text message in time to purchase tickets when early bird tickets are replenished. Therefore, early bird ticket out of stock registration is Replenishment notification means. Early bird tickets refer to general airline or hotel promotions, a marketing model for organizers to attract consumers on ticket sales.