Would you be “permitted” to hole up in your house/apartment?
An infected person who chooses to remain at home (or undiagnosed person) could meet some pressure from “authorities”.
Pressure should’ve been put on points of entry. The powers that be refused to do that.
We may not be able to screen and observe when they get on a plane but we can hold them at customs and deny entry if we choose to.
This should have covered the problem, seems to me:
“Whenever the Surgeon General determines that by reason of the existence of any communicable disease in a foreign country there is serious danger of the introduction of such disease into the United States, and that this danger is so increased by the introduction of persons or property from such country that a suspension of the right to introduce such persons and property is required in the interest of the public health, the Surgeon General, in accordance with regulations approved by the President, shall have the power to prohibit, in whole or in part, the introduction of persons and property from such countries or places as he shall designate in order to avert such danger, and for such period of time as he may deem necessary for such purpose.”
http://www.cdc.gov/quarantine/specificlawsregulations.html