So your supposed to store the grub passwords in a safe? What happens if you forget the safe combination? Maybe you should put the safe combination in another safe. But what happens if you forget the combination to that safe? Maybe it's then time to get out the torch. I guess that means it is possible to gain root on a Linux box with a blow torch.
Of course I would just boot from alternate media and mount the drive (move the drives to another machine if necessary) and wipe the root password from /etc/shadow. Sorry, just trying to be funny.