I hope you're right, but one thing to remember is that if the person was a terrorist, the fact that they know they are infectious wouldn't hinder them from getting on a plane.
In all fairness though, we know almost nothing about the person that was checked, so I guess the wisest thing for us - meaning those of us that wouldn't be able to do anything about it anyway - to do for now is to wait and see what happens.
So far, I haven't seen much here to make me that anxious about it yet. Even if it is true, the fact that we know about it so soon means it can probably be contained quickly.
Gamma
It has nothing to do with me. Please read the links I've given. They will give you all the information you will need.
From another site:
A person infected with smallpox and overtly sick usually transmits the virus face-to-face in a closed dwelling. There is no infectious subclinical state.