Deleting a folder (or user) using cyradm with Cyrus IMAP

I decided to clean out some older users I have on my Cyrus IMAP server. The documentation says to do e.g.

> sam user.foo cyradm d
> dm user.foo

This however did not work for me, even though the "d" flag is what the docs says. Searching the Cyrus forums, I found out that the permission for the admin user has to be set to "c" for the user / folder to delete. So I did

> sam user.foo cyradm cd
> dm user.foo

And things works fine agin.