Benford Law applies to anything where values appreciate or depreciate exponentially. Kind of weird to see it relate to passcodes (where it isn't really Benford's Law at all, but instead is simply numeric proximity), but for monetary values, forces of nature, population counts, etc, Benford's Law will always apply to a large enough set, for reasons that become very evident once you understand the reasoning.

http://blog.yafla.com/Demystifying_Benfords_Law

Best page I've seen on it.