In today's blog post at http://www.legalgenealogist.com/2016/12/21/the-dog-that-did-bark/, Judy Russell corrected her response to a question posed at the end of her BCG webinar on negative evidence last night. As she writes, "The question was whether DNA results could be negative evidence, and, in my answer, the example I used of a case that could be negative evidence… isn’t," and she goes on to explain why.
I'm wondering under what circumstances DNA evidence might in fact be negative evidence. Would a non-paternity event where there evidence of "a break in the link between an hereditary surname and the Y-chromosome resulting in a son using a different surname from that of his biological father" (from http://isogg.wiki/Non-paternity_event) be an example of negative evidence? Or is this simply direct evidence?
Any other examples?