Lord Nicholls on the likelihood of crimes

In the decision to the British appeals case Re H (Minors), Judge Lord Nicholls, talking about criminal behavior, stated that “that the more serious the allegation the less likely it is that the event occurred”. There is actually quite a bit of discussion about the conclusions that should be drawn from this observation in the literature, but I have not found much discussion of the question whether the observation is right . I find this surprising, and in this essay I want to inspect this question.