I get annoyed at apologists and theists that trot “absence of evidence is not evidence of absence” out as if it is some kind of unbreakable law. Nonsense. Not only is it the basis of a gazillion court cases, as well as carefully constructed scientific experiments, it is very useful to boot. It CAN be a fallacy when formulated as an Argument from Ignorance, but it is not strictly synonymous. John D. Cook, mathematician and statistician, sums it up well. Also, Carrier in Proving History deals really well with it as not being a fallacy in historical analyses. JohnM has recently being claiming this mantra incorrectly.