An Expo passport with a price of 30 yuan will be able to shout a high price of 5000 yuan on the Internet if it covers more than 200 exhibition hall stamps. However, this "sky passport" is no longer difficult to "mass production", because some venues have quietly set the cap limit, will "passport cattle" shut out.

Expo passport is almost an essential part of visitors' view. It is interesting to build a chapter in a library, collecting and collecting it. However, this also lets many people find business opportunities, so in the park can often see a stack of even a bag of passports, in the various venues knocking on the stage "bombardment" "passport cattle", so that the staff and the tourists waiting behind can not eat. The staff of the Canadian Pavilion complained to reporters: "once someone took 400 passports and asked for a seal, but he refused to accept it."

In order to prevent such a situation from repeating itself, some venues have set up the upper limit of the seal. According to the Oriental web reporter, there was a notice on the knockout section of the Irish Pavilion marking "5 chapters for each visitor to cover the museum." In addition, Canada, Sweden and other venues will set the cap to 3. This practice has greatly shortened the time for tourists to queue up for stamping, and has been well received.