There is a conflict between people over a 72 hr visit.

Hi Emilly, as what listed on the other page, according to presentations by Beijing PSB officers, the 72 hours will be counted from the moment visitors get their transit permits, but not the time when they land at the airport. However, different airlines may have different policies regarding this visa free transit. For example, passengers may be denied boarding their flights if they do not have confirmed tickets for leaving within 72 hours (here the 72 hour can be simply calculated based on scheduled landing and scheduled departure of the flights). So, you are suggested to book a flight ticket for leaving within 72 hours to a third country or region. Or it is wise to apply for a visa in advance.