
Generally I think your point is valid. However, I don't think so in thise case.
To me, the old saying "Fool me once, shame on you. Fool me twice, shame on me" applies here. If you really want to break this down, she wasn't scammed once. She was scammed several times... in the same way... by the same person. Honestly, I don't see how you can look at it and say she was completely blameless in the matter.
To use your anology:
If you leave that stack of 20 dollar bills, yes, it's my decision to steal them. However, if you do so every day for the next month, and every day I take them in the same way, are you not a little more than stupid at that point? Would you not be somewhat to blame for your own misfortune? Surely you don't think you can claim it was 100% my doing after it had happened over and over and over again.
We all like praise, but a hike in our pay is the best kind of ways.