Papers Please !! Literally

https://californiaglobe.com/section-2/los-angeles-to-introduce-mandatory-air-rail-travel-forms-starting-wednesday/

On Monday, Los Angeles Mayor Eric Garcetti instituted severe new measures to air and rail travel in the city only days before Thanksgiving

Starting Wednesday, all out of state and out of country passengers over the age of 16 travelling into Los Angeles International Airport, Van Nuys Airport, or Union Station will need to sign a “Traveler Form” before arriving into the city. The form, similar to the mandatory New York travel form, makes sure that passengers have read and understood the California travel advisory, in addition to potentially helping with contact tracing should cases of COVID-19 be reported. It can either be filled out online before arrival or be given in paper on arrival. If a passenger does not fill out the form, a fine of up to $500 will be issued.