Every law has its exception:

Adolf Hitler --> Anabolic steroid --> Peliosis hepatis --> Fecal enema

This law never will have exceptions that last long. Once its Wikipedia entry lists an exception, it no longer will be an exception, as the listing creates a path of length 2.

Ah, but then the article would have to be edited to remove the false exception, thus making the exception valid again.

It seems we've arrived at a proof that Wikipedia in fact can not have perfect, comprehensive knowledge of the world.