"Not only is it humiliating but it makes me wonder about my own sense of observation--is it defective, to not have noticed these things? Have I become complacent?"

I haven't been saying much on this subject, but no, there's nothing wrong about your sense of observation. There's very little you can do about something like this; we detect threats and lies and danger like this by comparing what we're being told to the observable evidence around us. However, in this situation, the interface separating the two of you was large enough to preclude any attempt to compare the situations presented. And the easiest trick, to find things that don't match in recitations of daily life, doesn't work because the distance was enough that I suspect real details were used; meaning that there were very few small details to mess up in the recitation; descriptions of dwellings, surroundings, and daily routine are all probably real. It's almost impossible to catch these people when so little of your real, observable life intersects with them. There's nothing wrong with you; I'm sure you would have noticed if the approach had changed to trying to get money or other favors out of you that would have been against your best interests to provide, or otherwise directly taking advantage of you. Each of us probably has defenses and observational skills geared toward direct attacks, not manipulation that views us incidental to its true aim.

I don't know if that made any sense, but I don't think there's anything you have to be worried about or embarrassed of. I'm the farthest removed from all of this mess probably of the people who still remember all the players, and perhaps that's why I'm one of the least affected, but from where I stand there's very little you could have expected yourself to do within the bounds of reason. I hope I didn't do anything to contribute to it, and I hope you can put this situation where it rightfully belongs soon, behind you, in the trash bin.