It's also an experiment. They need to know how people react and change their behavior with this cheap ticket. And they still need to check tickets anyway. And t

It's also an experiment. They need to know how people react and change their behavior with this cheap ticket. And they still need to check tickets anyway. And the price also serves as a kind of barrier to animate people to at least thing a moment, whether they really need the ticket and can "waste" the monety for it.