How about the guy that sat in the same seat on the next flight? This is out of the bag and impossible to track?
Also, a friend who is an ID, said that the re-circulation of the air we breath on any plane, redistributes all viruses and germs carried by any/every passenger on that plane to everyone breathing that air on that trip.
Then unless everything is sterilized, the next passengers get the germ/virus bonuses left by the previous passengers for hours if not days.
That’s why all this talk of closing borders and quarantine is way too late. The virus is out there circulating and we will soon know what we are dealing with.