Ticket System: Missing Error Handling

(1) No description of what happens if the credit card is invalid

(2) No description of what happens if the user enters an incorrect personal identifier

(3) No description of what happens if the selected destination is not available on the current day

(4) No description of what happens if the user changes their mind and wants to cancel before the ticket is issued

Explanation

The key omissions in the ticket system description relate to error handling and exception cases: invalid card, wrong PIN/identifier, unavailable destination, and cancellation mid-transaction. These are all critical for a real ticket-issuing system. Seating class is a feature/product decision, not a missing requirement implied by the description.