Ampersands in #+AUTHOR: declarations are not correctly escaped by Org-mode.
To reproduce, export:
#+AUTHOR: a & b
You'll find the line
in the output, but it should be
The same problem occurs with other special characters in author
declarations, and also in #+DATE: declarations.
This is breaking the "XHTML 1.0 Strict" claim.
- Pavel Panchekha