Wait, what?

Here a delicious cake for you, anons. I'm learning NFS from the nfs howto...

http://nfs.sourceforge.net/nfs-howto/ar01s03.html

On the very beginning of the page, section 3.2, there's a link to... wait, what??

A few cautions are in order about what cannot (or should not) be exported. First, if a directory is exported, its parent and child directories cannot be exported if they are in the same filesystem. However, exporting both should not be necessary because listing the parent directory in the /etc/exports file will cause all underlying directories within that file system to be exported.

WHAT???