I was going to stay out of this but I can't.

You asked this from an "ethical" point of view but then tossed in the moral question which is different.

From an "ethical" standpoint, a buyer may be under no obligation to educate or assist a seller to his/her own detriment.

From a "moral" standpoint, we should not knowingly take advantage another human being and to profit from such may be a sin.

It is quite common to be ethically correct and morally wrong. Attorneys have made an entire profession out of it. How each of us deals with these questions defines what we call our "character".

I would like to think that I would not knowingly take advantage of an old uninformed widow for Christmas but hey... that's just me.

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shhhhhh turtles are sleeping....