No, the point is saying that she should have "known".
She didn't buy it out of the back of a trunk but at one of the most reputable auction houses in the world.
Why they signed off on it is undoubtedly a tale that should be investigated. The fact that she did not try to hide her ownership is a point in favor of her NOT knowing.
But she knows now. Rightfully it's not hers, legally it is now. I'm ok with that, but I find her actions interesting.
Just a note, till the 1998 treaty which essentially determined that all post 1933 German transactions were under duress, the nature of these pieces wasn't a secret. And it was assumed that the transactions were perfectly legal, that 1933 to 1945 didn't exist. The fact that it might be a NAZI piece wouldn't be a reason to conceal it. Interestingly some of the largest $$ cases in the last few years were initially pursued in the late 1940s, unsuccessfully. The rules did change post 98