Grub superuser password is required for login on 13.10

According to this documentation: https://help.ubuntu.com/community/Grub2/Passwords, I am supposed to be able to just set the superuser password to protect the grub entries. Why is grub asking for a password when booting into Ubuntu 13.10? How do I disable that?

I added the

set superusers="John"
password John foo
export superusers

to the /etc/grub.d/40_custom