Passengers who "buy short and take long" may face “persuasion to get off” by the conductor. It is not recommended that passengers purchase short-distance tickets and then get on the train to make up for the tickets.
If the train is overcrowded or has reached the capacity limit, tickets may not be replaced. If you ride with an invalid ticket or continue riding without getting off the ticket after arriving at the station, you will be treated as having no ticket.