A lot of this is preparedness. Most Asian airports I have been to already have infrared imaging in place - they have been in place for years due to the original SARS.
I came back through SFO the end of January. Other than signs on the TV saying "If you were in WuHan...", they did not seem to be prepared at all. The DHS lady who collected my Global Entry form got kind of defensive when I asked her what they are doing about it.
The scary thing is that some of them can have it already or catch it while they wait. Then they have domestic flights home - the TSA agent who checks their documents, virus gets on other people's documents, passengers / FAs on the flights...
In a few days, this won't be a problem.