From my experience so far the Hotel reservation for the first night seems to be even more important than the onward flight ticket.

As I have booked most of my flights , hotels etc. while travelling and e.g. the Bear Capsule Hostel in Taipeh did not offer a printing service I only had screenshots, which are sufficient...as long as they also include the flight number.

I am just wondering how they deal with the Air Serbia flights from Belgrade to Tianjin.

Maybe they have customs and immigration staff who can understand/speak English. The ones on duty during my arrival from Osaka could not, but the state security agents have been fluent in English and really helpful/supportive.

They cannot send so many state security agents to the Airport every single time a flight arrives from Belgrade, or can they ?