Now that tourist tickets are scanned with QR codes, how can I know if they have been used?

the QR code is unique, which is equivalent to a person's ID card. It contains about 2 characters of information such as letters, numbers, images and sounds. One QR code corresponds to a ticket, which can fully confirm the validity of the ticket. Once it is scanned, the system information will no longer be valid. Brushing again will prompt when it has been brushed and give an alarm prompt. Don't be afraid of being caught and fined. You can try.