If the money that was given away by a seemingly very generous donor was illegally gained, can the nonprofits who benefited from the donor's largesskeep the money? What's an example: Madoff where the question is certainly being answered in the courts.
Meanwhile, and this is probably something nonprofits in every state should consider, in Minnesota the legislature has an answer: create legislation that protects the nonprofits. For more details, see the Wall Street Journal article.
I would offer though that the premise behind protecting nonprofits is that they have no clue about the source and they are of course doing good things. But when nonprofits invest in "too good to be true" investments and receive large gifts from sources they can't really explain or even fully understand why them, does this truly deserve blind absolution? I'm not so sure.