All such scenarios are based on probability. The problem with them is that there is also a probability that some method of contact with fluids happened that is more remote.
If I were in charge, with someone showing signs of a possible ebola infection, I would have quarantined everyone until a rt-pcr came back on the possible patients.
Unfortunately, most management positions in the CDC are political, and would not want to make bho look bad, and would not want to do anything that could affect air travel, or lead to possible restrictions on travel from africa. Therefore, the patients would be taken off, and the passengers let go, even if there was a high suspicion of ebola.
A prudent, responsible person, might quarantine likely passengers, but, how many people used the bathrooms the patients used? what seat arm rest did the sick patients touch going up and down the aisles? etc.
I'm afraid that, since the guy in texas made it here and is getting medical care, others in affected countries are going to start doing the same thing, and this country will see multiple incidents of exposure AND INFECTION within the next few weeks.