Yes, but someone at the airport has to examine your passport with focus. My passport has many pages stamped with visits to the 36 countries I have traveled to. May not be practical. All they are doing is taking quick body temperature with a gadget pointed at the forehead.
Yes but to go TO China as a foriegn national, your passport will have a full page China visa approving dates of travel and VERY easily visible. Passport only has, what, 21 usable pages and the China visa is easy to spot. We’re not talking entry/exit stamps that are 1/4-page sized inked stamps.
Again a China visa is a full page, clear as day. To flip through a paper for one takes turning ten pages. Stands right out. China is not like the UK, or France, where no visa is required. To go to China (on a us passport) you send you passport to their embassy within one month of departure for a visa, which is limited use date range and that is clearly unique one page decal. One passport may have a few visas taking up whole pages.
Obviously if your a Chinese national, that passport will easily be recognised and scrutinized even further for exit/entry visas.
Not difficult, to determine either way.