Well, I don't buy this in general, but I do know one person who would do this. I was talking with her recently about a lottery winnery who won some huge sum, maybe $100M, and she said, "But it ruined his life." And I said, "Why? What happened?" And she said, "Oh, I don't know what happened. But I assume it ruined his life."

In her mind, I think she had already taken her high prior for B, assumed B, and converted the non-incident into further evidence for B. She did laugh at herself when she realized she'd done this, so there is hope. :)