I needed to set my Apache Web Server to ignore/block all the HEAD requests but respond to GET requests normally. It is very simple with the mod_rewrite, for instance this can be added to .htaccess:

RewriteEngine   On
RewriteCond     %{REQUEST_METHOD} HEAD
RewriteRule     ^.*$    - [F]

Second line:

RewriteCond     %{REQUEST_METHOD} HEAD

matches all requests that use method HEAD.

Third line:

RewriteRule     ^.*$    - [F]

tells Apache HTTP not to make any redirection (-) and sends back HTTP 403 (FORBIDDEN).