When we book a movie ticket through online ticket booking system, after the payment we get the ticket in PDF format and whosoever has that PDF, can claim to be the owner of the movie ticket. So if someone booked the ticket for you and send you the ticket, he can still claim to be the owner of the ticket even if you've paid him the money. Also there are high chances of ticket forgery and majority of the time when there's a data breach, the users data is leaked and their payment details also get exposed.