Two different things here. Some BIOS's offer a "boot" password.
Start up will not continue without this password, including entering
the BIOS. LiveCD does not bypass this.
Grub/Lilo password protects the "bootloader", preventing
access to the Operating System and protecting the boot options from
being changed. Ex: edit Grub and append "1", "s", "single" and the
system is booted into "maintenance"/"single user" mode as root.
Current systems: WHAT OS, BackTrack-raw, PCLinuxOS, Peppermint OS 6, Kali Linux
and a custom Linux From Scratch server hosting a bunch of top secret stuff.