So seems free WordPress Themes may not be safe.

http://www.blogher.com/frame.php?url=http://wpmu.org/why-you-should-never-search-for-free-wordpress-themes-in-google-or-anywhere-else/

http://wpmu.org/when-is-a-free-wordpress-theme-really-free-some-thoughts-and-some-places-to-find-them/