How can I check if an album has subalbums in the theme's album.php file?

This is because I don't want users to be able to download zip files containing a bunch of albums. Using printAlbumZip(), it creates over a GB size zip files which can't be downloaded over HTTP anyway (limit should be around 350MB).

http://www.zenphoto.org/documentation/functions/_template-functions.php.html#functiongetNumAlbums