Apache: The Definitive Guide, 3rd Edition

Stopping users overriding system-wide settings...

To run a really tight ship, you’ll want to stop users from setting up .htaccess files that can override security features you’ve configured. Here’s one way to do it: in the server configuration file, add the following:

<Directory /> 
AllowOverride None 
Options None 
Allow from all 
</Directory>

then set up for specific directories. This stops all overrides, includes, and accesses in all directories apart from those named.