I think the lady was a nitwit, but I’m not sure anybody else was. Once you have a “say something” regime in place, you have to act when somebody says something. In this case, the woman wrote a note that said she was sick, and then when she got off the plane, she revealed that she thought her seatmate was acting suspiciously. I suspect that at that point, no matter how she describes (or fails to describe) the suspicious behavior, no airline employee is going to simply disregard it. They will have to do at least what they did, which is interview the supposedly suspicious individual. Most likely, the big delay was because somebody with enough authority to decide that nothing suspicious was going on had to be summoned.
In other words, I suspect something similar would have happened if she had just said, “I don’t know, there’s something off about him–I think he’s suspicious” with no further details at all. To this extent, the terrorists have already won, but I’m not sure what can be done about it.