@Hostco,
If you check his signature, you'll find that he's not.
@HWF,
If I understand correctly, you want to delete all unused websites? The problems with deleting all websites with 0Mb used is as follows:
1) WHM data is cached, as Glenn pointed out, so the value might have changed since then.
2) If a client has a very small website, such that it shows up as 0, then it will be deleted as well. There are some potentially useful applications where you don't need a large website, such as if your website is a simple PHP script tool for people to use.
The best way to do this is to also check the file contents. You should have a default page you set up in the cpanel3-skel folder, and so you can visit the website in PHP to see if it matches. (If you didn't, it will be empty so check for that.)
Run both tests for all your files, in a PHP script, and you can have it generate a link to the 'Terminate Multiple Accounts' feature in the WHM. You'll find this script will come in handy later too.