comment: >
  
  I've travelled a lot and MOST countries have biometric passports. In customs lines, I still see some people without biometric passports now and again. I imagine that a number of these people are from countries that do have biometric passports, but they have an older passport that hasn't expired yet.
  Also, I've noticed that customs deal with folks from countries that have diplomatically adversarial relationships differently. They rely more on paper visas and stamps than electronic records. So I'm not sure how much the US government trusts the more technologically advanced passports from China. But a mix of old and new technologies is definitely used by border officials.
  Anecdotally, as an American, my passport does not get stamped for countries like Australia and Canada. Most European countries will still physically stamp it, especially if the country is your first entry into the Schengen Region. And China? They put a paper visa on an entire page of my passport.
context: People from China will travel through Europe and come in to America from the east coast like they did when the pandemic started. This will do nothing if all travelers aboard aren’t made to test. >
  
  I agree.
  Although part of the rule is that you must get tested if you were in China 10 days prior to your departure from China to anywhere basically. 
  I’m not sure how they will enforce this but I guess it’s supposed to work.. >
  
  Passports show a history of where somebody has been. They're literally stamped. >
  
  I think they're scanned now instead of visually confirming the stamps. Which is even easier. >
  
  yeah there is definitely a digital aspect to it, just not sure exactly what >
  
  Every country has scanners, every country does biometrics. Even crossing the border to some 3rd world country like Cambodia, they scan your finger prints and take a picture, scan your passport. They know where you have been. 
  Where you run into an issue is dual citizenship or green cards. Someone from China could enter China using their Chinese passport, but enter the US on a green card. US has no real idea you were in China.