If the plane's going down, you're going down no matter what, a specific seat is not going to save you nor is there a "safest seat". That safest seat is at the gate. They should have just taken their assigned seat and sat.
A situation similar to this happened to me (a lot more serious) and I just notified the TSA as I was walking out as a precaution, I didn't make a huge deal. It did happen to be on an Airtran flight to Florida, too, a few years ago.

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Remember also, we have no idea if AirTran officials were given a "warning" in the last few days to look out for possible terrorist exercises. These are things Joe Public will never know.

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An unwavering defender of those I see worth protecting.

"promote the general welfare, not provide the general welfare"

We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America.

I have flown many times to Taiwan, and believe me, last thing I wanna hear is someone talking about 911 or terrorists. I already have a fear of flying, and that kinda talk is not acceptable period. On the other hand, I have had that discussion about the safest seat on a plane with my wife many times. Nothing wrong with that, but if that discussion includes bombs, terrorists and other none cool things to talk about on a plane then it should not be spoken.