Here's a strange thing: in Beijing, undergraduate students at Peking University are only allowed to date students from their own school or Tsinghua University.

Because if you date students from other universities besides Tsinghua or Peking, you'll face the awkward situation of your boyfriend/girlfriend not being able to enter their own school.
The reason is that Peking University students can only invite friends or family into campus a maximum of 8 times per month.
After 8 times, they have to compete with visitors for tickets, which is almost hopeless, and you need to make reservations 7 days in advance.
Reselling on Xianyu or through scalpers has already reached 150 yuan, while Tsinghua is probably only 50-80 yuan, because Tsinghua students can bring friends or family without any limit on the number of visits.
Now, the campuses of Tsinghua and Peking University are like foreign countries—entry requires a visa.
Between Tsinghua and Peking University, there’s mutual visa exemption, and students can swipe their campus cards to enter each other's schools.
Students from Renmin University, Lin University, and Physical Education University who want to get in find it quite difficult; they need to book an appointment 7 days in advance, or they have to buy from scalpers. 🤣